diff --git a/742a.cpp b/742a.cpp
new file mode 100644
index 0000000..68e480c
--- /dev/null
+++ b/742a.cpp
@@ -0,0 +1 @@
+cp
\ No newline at end of file
diff --git a/757c.cpp b/757c.cpp
new file mode 100644
index 0000000..481f73b
--- /dev/null
+++ b/757c.cpp
@@ -0,0 +1,64 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<ll, ll>;
+using vi = vector<ll>;
+using vpi = vector<pi>;
+using vb = vector<bool>;
+
+const ll mod = 1e9 + 7;
+
+ll binpow(ll x, ll n, ll m) {
+    assert(n >= 0);
+
+    x %= m;  // note: m * m must be less than 2^63 to avoid ll overflow
+
+    ll res = 1;
+
+    while (n > 0) {
+        if (n % 2 == 1)  // if n is odd
+
+            res = res * x % m;
+
+        x = x * x % m;
+
+        n /= 2;  // divide by two
+    }
+
+    return res;
+}
+
+void solve() {
+    ll n, m;
+    cin >> n >> m;
+
+    ll orsum = 0;
+    for (ll i = 0; i < m; i++) {
+        ll x, y, a;
+        cin >> x >> y >> a;
+        orsum |= a;
+    }
+
+    ll ans = 0;
+    ll i = 0;
+    while (orsum > 0) {
+        if (orsum & 1) ans += binpow(2, n - 1 + i, mod);
+        ans %= mod;
+        orsum >>= 1;
+        i++;
+    }
+
+    cout << ans << endl;
+}
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+
+    ll t;
+    cin >> t;
+    while(t--) solve();
+
+    return 0;
+}
\ No newline at end of file
diff --git a/arena1.cpp b/arena1.cpp
new file mode 100644
index 0000000..e8415ac
--- /dev/null
+++ b/arena1.cpp
@@ -0,0 +1,47 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<ll, ll>;
+using vi = vector<ll>;
+using vpi = vector<pi>;
+using vb = vector<bool>;
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+
+    const int mod = 998244353;
+
+    ll n, x;
+    cin >> n >> x;
+
+    vector<vi> power(x + 1, vi(n + 1));
+    vector<vi> c(n + 1, vi(n + 1));
+
+    for (int i = 0; i <= x; i += 1)
+        for (int j = 0; j <= n; j += 1)
+            power[i][j] = j ? power[i][j - 1] * i % mod : 1;
+    for (int i = 0; i <= n; i += 1)
+        for (int j = 0; j <= i; j += 1)
+            c[i][j] = j ? (c[i - 1][j - 1] + c[i - 1][j]) % mod : 1;
+
+    vector<vi> dp(n + 1, vi(x + 1));
+
+    for (int i = 0; i < x + 1; i++) {
+        dp[1][i] = x - i + 1;
+    }
+
+    for (int i = 2; i <= n; i++) {
+        for (int j = x; j >= 1; j--) {
+            for (int k = 0; k <= i; k++) {
+                if (j + i - 1 < x + 1) dp[i][j] += ((dp[k][j + i - 1] * c[i][i - k]) % mod * power[i - 1][i - k]) % mod;
+                dp[i][j] %= mod;
+            }
+        }
+    }
+
+    cout << (power[x][n] + mod - dp[n][1]) % mod << endl;
+
+    return 0;
+}
\ No newline at end of file
diff --git a/dela.cpp b/dela.cpp
new file mode 100644
index 0000000..73770f8
--- /dev/null
+++ b/dela.cpp
@@ -0,0 +1,42 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<ll, ll>;
+using vi = vector<ll>;
+using vpi = vector<pi>;
+using vb = vector<bool>;
+
+void solve() {
+    ll n;
+    cin >> n;
+
+    vi a(n);
+    for(ll i = 0; i < n; i++) {
+        cin >> a[i];
+    }
+
+    ll mx = 0;
+    ll cnt = 0;
+    ll sum = 0;
+    for (ll i = 0; i < n; i++) {
+        ll cur = a[i];
+        while (cur % 2 == 0) cur /= 2, cnt++;
+        mx = max(mx, cur);
+        sum += cur;
+    }
+
+    cout.precision(62);
+    cout << ((sum - mx) + mx * pow(2, cnt)) << endl;
+}
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+
+    ll t;
+    cin >> t;
+    while(t--) solve();
+
+    return 0;
+}
\ No newline at end of file
diff --git a/delb.cpp b/delb.cpp
new file mode 100644
index 0000000..5019ed6
--- /dev/null
+++ b/delb.cpp
@@ -0,0 +1,53 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<ll, ll>;
+using vi = vector<ll>;
+using vpi = vector<pi>;
+using vb = vector<bool>;
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+
+    ll n, q;
+    cin >> n >> q;
+
+    string s;
+    cin >> s >> ws;
+
+    ll sum = 0;
+
+    for (ll i = 0; i < n - 2; i++) {
+        if (s[i] == 'a' && s[i + 1] == 'b' && s[i + 2] == 'c') sum++;
+    }
+
+    for (ll j = 0; j < q; j++) {
+        ll i;
+        char c;
+        cin >> i >> c;
+        i--;
+
+        ll bsum = 0;
+
+        for (ll k = i - 2; k <= i; k++) {
+            if (k + 2 >= n || k < 0) continue;
+            if (s[k] == 'a' && s[k + 1] == 'b' && s[k + 2] == 'c') bsum++;
+        }
+
+        s[i] = c;
+
+        ll nsum = 0;
+
+        for (ll k = i - 2; k <= i; k++) {
+            if (k + 2 >= n || k < 0) continue;
+            if (s[k] == 'a' && s[k + 1] == 'b' && s[k + 2] == 'c') nsum++;
+        }
+
+        sum += nsum - bsum;
+        cout << sum << endl;
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/delc.cpp b/delc.cpp
new file mode 100644
index 0000000..65b4c2c
--- /dev/null
+++ b/delc.cpp
@@ -0,0 +1,92 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<ll, ll>;
+using vi = vector<ll>;
+using vpi = vector<pi>;
+using vb = vector<bool>;
+
+vb prime(1e6 + 8, true);
+
+void solve() {
+    ll n, e;
+    cin >> n >> e;
+
+    vi a(n);
+    for(ll i = 0; i < n; i++) {
+        cin >> a[i];
+    }
+
+    vb all1(n);
+    vb works(n);
+    vi sum(n);
+    vi sum2(n);
+
+    ll tot = 0;
+
+    for (ll i = 0; i < n; i++) {
+        ll last = i - e;
+
+        if(last < 0) {
+            if (a[i] == 1) {
+                all1[i] = true;
+                sum[i] = 1;
+            } else if (prime[a[i]]) {
+                works[i] = true;
+                sum[i] = 1;
+            }
+        } else {
+            if(all1[last]) {
+                if(a[i] == 1) {
+                    all1[i] = true;
+                    sum[i] = sum[last] + 1;
+                } else if (prime[a[i]]) {
+                    works[i] = true;
+                    sum[i] = sum[last] + 1;
+                }
+            } else if(works[last]) {
+                if(a[i] == 1) {
+                    works[i] = true;
+                    sum[i] = sum[last];
+                    sum2[i] = sum2[last] + 1;
+                }
+            } 
+            
+        }
+        if(!works[i] && !all1[i]) {
+            if (a[i] == 1) {
+                all1[i] = true;
+                sum[i] = 1;
+            } else if (prime[a[i]]) {
+                works[i] = true;
+                sum[i] = max((ll)1, sum2[last] + (ll)1);
+                tot += sum[i] - 1;
+            }
+        } else {
+            if(works[i] && last >= 0) tot += sum[last]; 
+        }
+    }
+
+    cout << tot << endl;
+}
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+
+    prime[0] = prime[1] = false;
+    for (ll i = 2; i < (1e6+8); i++) {
+        if (prime[i] && (long long)i * i < (1e6+8)) {
+            for (ll j = i * i; j < (1e6+8); j += i)
+                prime[j] = false;
+        }
+    }
+
+
+    ll t;
+    cin >> t;
+    while(t--) solve();
+
+    return 0;
+}
\ No newline at end of file
diff --git a/delcbad.cpp b/delcbad.cpp
new file mode 100644
index 0000000..8328a20
--- /dev/null
+++ b/delcbad.cpp
@@ -0,0 +1,54 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<ll, ll>;
+using vi = vector<ll>;
+using vpi = vector<pi>;
+using vb = vector<bool>;
+
+vb prime(1e6 + 8, true);
+
+void solve() {
+    ll n, e;
+    cin >> n >> e;
+
+    vi a(n+1);
+    for (ll i = 1; i <= n; i++) {
+        cin >> a[i];
+    }
+
+    ll tot = 0;
+
+    for (int i = 1; i <= n; i++) {
+        for (int k = 1; k <= n; k++) {
+            if (i + e * k > n) continue;
+            ll prod = 1;
+            for (int j = 0; j <= k; j++) {
+                prod *= a[i + e * j];
+            }
+
+            if (prime[prod]) tot++;
+        }
+    }
+
+    cout << tot << endl;
+}
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    prime[0] = prime[1] = false;
+    for (int i = 2; i < (1e6 + 8); i++) {
+        if (prime[i] && (long long)i * i < (1e6 + 8)) {
+            for (int j = i * i; j < (1e6 + 8); j += i)
+                prime[j] = false;
+        }
+    }
+
+    ll t;
+    cin >> t;
+    while (t--) solve();
+
+    return 0;
+}
\ No newline at end of file
diff --git a/delcbetter.cpp b/delcbetter.cpp
new file mode 100644
index 0000000..00c89dd
--- /dev/null
+++ b/delcbetter.cpp
@@ -0,0 +1,59 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<ll, ll>;
+using vi = vector<ll>;
+using vpi = vector<pi>;
+using vb = vector<bool>;
+
+vb prime(1e6 + 8, true);
+
+void solve() {
+    ll n, e;
+    cin >> n >> e;
+
+    vi a(n);
+    for (ll i = 0; i < n; i++) {
+        cin >> a[i];
+    }
+
+    ll ans = 0;
+    for (ll i = 0; i < n; i++) {
+        if (!prime[a[i]]) continue;
+        ll l, r;
+        l = r = i;
+        ll cnt0, cnt1;
+        cnt0 = cnt1 = 0;
+        while (l >= 0 && (a[l] == 1 || l == i)) {
+            cnt0++;
+            l -= e;
+        }
+        while (r < n && (a[r] == 1 || r == i)) {
+            cnt1++;
+            r += e;
+        }
+        ans += cnt0 * cnt1 - 1;
+    }
+
+    cout << ans << endl;
+}
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+
+    prime[0] = prime[1] = false;
+    for (ll i = 2; i < (1e6 + 8); i++) {
+        if (prime[i] && (long long)i * i < (1e6 + 8)) {
+            for (ll j = i * i; j < (1e6 + 8); j += i)
+                prime[j] = false;
+        }
+    }
+
+    ll t;
+    cin >> t;
+    while (t--) solve();
+
+    return 0;
+}
\ No newline at end of file
diff --git a/deld.cpp b/deld.cpp
new file mode 100644
index 0000000..c07a0b5
--- /dev/null
+++ b/deld.cpp
@@ -0,0 +1,82 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<ll, ll>;
+using vi = vector<ll>;
+using vpi = vector<pi>;
+using vb = vector<bool>;
+
+struct DSU {
+    vi par;
+    vi sz;
+
+    void init(ll n) {
+        for (ll i = 0; i < n; i++) {
+            par.push_back(i);
+            sz.push_back(1);
+        }
+    }
+    ll get_rep(ll node) {
+        if (par[node] == node) return node;
+        return get_rep(par[node]);
+    }
+    bool check_con(ll a, ll b) {
+        return get_rep(a) == get_rep(b);
+    }
+    void unite(ll a, ll b) {
+        ll x = get_rep(a);
+        ll y = get_rep(b);
+        if (x == y) return;
+        if (sz[x] < sz[y]) {
+            par[x] = y;
+            sz[y] += sz[x];
+        } else {
+            par[y] = x;
+            sz[x] += sz[y];
+        }
+    }
+};
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+
+    ll n, d;
+    cin >> n >> d;
+
+    DSU dsu;
+    dsu.init(n);
+
+    ll u = 0;
+    for (ll i = 0; i < d; i++) {
+        ll x, y;
+        cin >> x >> y;
+        x--, y--;
+
+        if(dsu.check_con(x, y)) {
+            u++;
+        } else {
+            dsu.unite(x, y);
+        }
+
+        multiset<ll, greater<ll>> szs;
+
+        for (ll j = 0; j < n; j++) {
+            if (dsu.get_rep(j) == j) szs.insert(dsu.sz[j]);
+        }
+
+        ll k = u + 1;
+        ll tot = 0;
+
+        for(ll j : szs) {
+            if (k == 0) break;
+            tot += j;
+            k--;
+        }
+
+        cout << tot - 1 << endl;
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/gen.cpp b/gen.cpp
new file mode 100644
index 0000000..c68fd93
--- /dev/null
+++ b/gen.cpp
@@ -0,0 +1,12 @@
+#include <bits/stdc++.h>
+using namespace std;
+int rnd(int a, int b) {
+    return a + rand() % (b - a + 1);
+}
+int main() {
+    srand(time(NULL));
+
+    int a = rnd(1, 10);
+    int b = rnd(1, 10);
+    cout << a << " " << b << endl;
+}
\ No newline at end of file
diff --git a/messages.cpp b/messages.cpp
new file mode 100644
index 0000000..35b5436
--- /dev/null
+++ b/messages.cpp
@@ -0,0 +1,63 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<ll, ll>;
+using vi = vector<ll>;
+using vpi = vector<pi>;
+using vb = vector<bool>;
+
+const ll N = 2e5 + 8;
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+
+    ll n;
+    cin >> n;
+
+    vi m(n);
+    vi k(n);
+    for (ll i = 0; i < n; i++) {
+        cin >> m[i] >> k[i];
+    }
+
+    ll bestt = 1;
+    ll bestans = 0;
+    vi bestpath;
+
+    for (ll t = 1; t <= 20; t++) {
+        vpi coeff(N);
+        for (ll i = 0; i < N; i++) {
+            coeff[i] = {0, i};
+        }
+        for (ll i = 0; i < n; i++) {
+            coeff[m[i]].first += min(t, k[i]);
+        }
+
+        sort(coeff.rbegin(), coeff.rend());
+
+        ll cans = 0;
+        vi path;
+        for (ll i = 0; i < t; i++) {
+            cans += coeff[i].first;
+            path.push_back(coeff[i].second);
+        }
+
+        if (cans * bestt > bestans * t) {
+            bestans = cans;
+            bestt = t;
+            bestpath = path;
+        }
+    }
+
+    cout << bestt << endl;
+
+    for (ll i = 0; i < bestt; i++) {
+        cout << bestpath[i] << " ";
+    }
+
+    cout << endl;
+
+    return 0;
+}
\ No newline at end of file
diff --git a/mmoo.cpp b/mmoo.cpp
new file mode 100644
index 0000000..c57a28e
--- /dev/null
+++ b/mmoo.cpp
@@ -0,0 +1,42 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<ll, ll>;
+using vi = vector<ll>;
+using vpi = vector<pi>;
+using vb = vector<bool>;
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+
+    ll n;
+    cin >> n;
+
+    vector<vi> a(n, vi(n));
+    for (int i = 0; i < n; i++) {
+        for(int j = 0; j < n; j++) {
+            cin >> a[i][j];
+        }
+    }
+
+    vector<vector<bool>> visited(n, vector<bool>(n, 0));
+    
+    
+    function<void(ll, ll)> ff = [&](ll x, ll y) {
+        if (x < 0 || x >= n || y < 0 || y >= n) return;
+        if (visited[x][y]) return;
+    
+        visited[x][y] = true;
+    
+        ff(x + 1, y);
+        ff(x - 1, y);
+        ff(x, y + 1);
+        ff(x, y - 1);
+    }
+
+
+
+    return 0;
+}
\ No newline at end of file
diff --git a/nekoc.cpp b/nekoc.cpp
new file mode 100644
index 0000000..763b356
--- /dev/null
+++ b/nekoc.cpp
@@ -0,0 +1,49 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<ll, ll>;
+using vi = vector<ll>;
+using vpi = vector<pi>;
+using vb = vector<bool>;
+
+const ll INF = 1e9;
+
+long long gcd(ll a, ll b) {
+    if (b == 0)
+        return a;
+    return gcd(b, a % b);
+}
+
+long long lcm(ll a, ll b) {
+    return (a / gcd(a, b)) * b;
+}
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+
+    ll a, b;
+    cin >> a >> b;
+
+    if (a > b) swap(a, b);
+    ll d = b - a;
+    ll best = lcm(a, b);
+    ll bestk = 0;
+
+    for (ll i = 1; i * i <= d; i++) {
+        if (d % i != 0) continue;
+        for (ll j = 0; j < 2; j++) {
+            ll k = i - (a % i);
+            ll l = lcm(a + k, b + k);
+            if (l < best) best = l, bestk = k;
+            if (l == best && k < bestk) bestk = k;
+            if (i * i == d) break;
+            i = d / i;
+        }
+    }
+
+    cout << bestk << endl;
+
+    return 0;
+}
\ No newline at end of file
diff --git a/nekocbad.cpp b/nekocbad.cpp
new file mode 100644
index 0000000..f1b0129
--- /dev/null
+++ b/nekocbad.cpp
@@ -0,0 +1,85 @@
+// C++ program for the above approach
+
+#include "bits/stdc++.h"
+using namespace std;
+
+// Function for finding all divisors
+// of a given number
+vector<int> getDivisors(int diff) {
+    // Stores the divisors of the
+    // number diff
+    vector<int> divisor;
+
+    for (int i = 1; i * i <= diff; i++) {
+        // If diff is a perfect square
+        if (i == diff / i) {
+            divisor.push_back(i);
+            continue;
+        }
+
+        // If i divides diff then
+        // diff / i also a divisor
+        if (diff % i == 0) {
+            divisor.push_back(i);
+            divisor.push_back(diff / i);
+        }
+    }
+
+    // Return the divisors stored
+    return divisor;
+}
+
+// Function to find smallest integer x
+// such that LCM of (A + X) and (B + X)
+// is minimized
+int findTheSmallestX(int a, int b) {
+    int diff = b - a;
+
+    // Find all the divisors of diff
+    vector<int> divisor = getDivisors(diff);
+
+    // Find LCM of a and b
+    int lcm = (a * b) / __gcd(a, b);
+
+    int ans = 0;
+
+    for (int i = 0;
+         i < (int)divisor.size(); i++) {
+        // From equation x = M - a % M
+        // here M = divisor[i]
+        int x = (divisor[i] - (a % divisor[i]));
+
+        // If already checked for x == 0
+        if (!x)
+            continue;
+
+        // Find the product
+        int product = (b + x) * (a + x);
+
+        // Find the GCD
+        int tempGCD = __gcd(a + x, b + x);
+        int tempLCM = product / tempGCD;
+
+        // If current lcm is minimum
+        // than previous lcm, update ans
+        if (lcm > tempLCM) {
+            ans = x;
+            lcm = tempLCM;
+        }
+    }
+
+    // Print the number added
+    cout << ans << endl;
+}
+
+// Driver Code
+int main() {
+    // Given A & B
+    int A, B;
+    cin >> A >> B;
+
+    // Function Call
+    findTheSmallestX(A, B);
+
+    return 0;
+}
diff --git a/nekocbadf.cpp b/nekocbadf.cpp
new file mode 100644
index 0000000..8c1d31d
--- /dev/null
+++ b/nekocbadf.cpp
@@ -0,0 +1,42 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<ll, ll>;
+using vi = vector<ll>;
+using vpi = vector<pi>;
+using vb = vector<bool>;
+
+const int INF = 1e9;
+
+// Recursive function to return gcd of a and b
+long long gcd(long long int a, long long int b) {
+    if (b == 0)
+        return a;
+    return gcd(b, a % b);
+}
+
+// Function to return LCM of two numbers
+long long lcm(int a, int b) {
+    return (a / gcd(a, b)) * b;
+}
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+
+    ll a, b;
+    cin >> a >> b;
+
+    int best = INF;
+    int bestk = -1;
+    cout << lcm(a, b) - max(a, b) << endl;
+    for (int k = 0; k < lcm(a, b) - max(a, b); k++) {
+        if (lcm(a + k, b + k) < best) best = lcm(a + k, b + k), bestk = k;
+        cout << k << " " << a + k << " " << b + k << " " << lcm(a + k, b + k) << endl;
+    }
+
+    cout << best << " " << bestk << endl;
+
+    return 0;
+}
\ No newline at end of file
diff --git a/nql.cpp b/nql.cpp
new file mode 100644
index 0000000..49bd1ab
--- /dev/null
+++ b/nql.cpp
@@ -0,0 +1,76 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<ll, ll>;
+using vi = vector<ll>;
+using vpi = vector<pi>;
+using vb = vector<bool>;
+
+const ll mod = 1e9+7;
+ll binpow(ll x, ll n, ll m) {
+    assert(n >= 0);
+
+    x %= m;  // note: m * m must be less than 2^63 to avoid ll overflow
+
+    ll res = 1;
+
+    while (n > 0) {
+        if (n % 2 == 1)  // if n is odd
+
+            res = res * x % m;
+
+        x = x * x % m;
+
+        n /= 2;  // divide by two
+    }
+
+    return res;
+}
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+
+    ll n;
+    cin >> n;
+
+    vi a(n);
+    ll esum = 0;
+
+    vi cnt(n);
+
+    for (ll i = 0; i < n; i++) {
+        cin >> a[i];
+        if (a[i] % 2 == 0) esum++;
+        while (a[i] % 2 == 0) a[i] /= 2, cnt[i]++;
+    }
+
+    vi r(31);
+    for (ll i = 0; i < n; i++) {
+        r[cnt[i]]++;
+    }
+
+    ll ans = 0;
+
+    ans += binpow(2, n, mod);
+    ans %= mod;
+    ans -= binpow(2, esum, mod);
+    ans %= mod;
+    ll sum = 1;
+
+    for (ll i = 30; i >= 1; i--) {
+        if(r[i] > 1) {
+            ans += (sum * (binpow(2, r[i] - 1, mod) - 1));
+        }
+        ans %= mod;
+
+        sum *= binpow(2, r[i], mod);
+        sum %= mod;
+    }
+
+    ans %= mod;
+
+    cout << ans << endl;
+
+    return 0;
+}
\ No newline at end of file
diff --git a/painta.cpp b/painta.cpp
new file mode 100644
index 0000000..56fc325
--- /dev/null
+++ b/painta.cpp
@@ -0,0 +1,64 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<ll, ll>;
+using vi = vector<ll>;
+using vpi = vector<pi>;
+using vb = vector<bool>;
+
+const ll INF = 1e9;
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+
+    ll n;
+    cin >> n;
+
+    vi a(n);
+    for (ll i = 0; i < n; i++) {
+        cin >> a[i];
+        a[i]--;
+    }
+
+    vi last(n, INF);
+    vi nxt(n, INF);
+    for (ll i = n - 1; i >= 0; i--) {
+        nxt[i] = last[a[i]];
+        last[a[i]] = i;
+    }
+
+    if (n < 2) {
+        cout << 1 << endl;
+        return 0;
+    }
+
+    ll l = 0;
+    ll r = 1;
+
+    if (a[l] == a[r]) l = r;
+
+    ll ans = 2;
+
+    for (ll i = 2; i < n; i++) {
+        if (a[i] == a[l] && a[i] == a[r]) {
+            l = r = i;
+        } else if (a[i] == a[l] || a[i] == a[r]) {
+            ans++;
+            l = r = i;
+        } else {
+            if (nxt[l] > nxt[r]) {
+                assert(l < i && nxt[l] > i);
+                r = i;
+            } else {
+                assert(r < i && nxt[r] > i);
+                l = i;
+            }
+            ans++;
+        }
+    }
+
+    cout << ans << endl;
+    return 0;
+}
\ No newline at end of file
diff --git a/paintabad.cpp b/paintabad.cpp
new file mode 100644
index 0000000..d7b6307
--- /dev/null
+++ b/paintabad.cpp
@@ -0,0 +1,47 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+const int MAXN = 100010;
+
+int n;
+int a[MAXN];
+int pos[MAXN], nxt[MAXN];
+
+void solve() {
+    scanf("%d", &n);
+    for (int i = 1; i <= n; ++i)
+        scanf("%d", &a[i]);
+    for (int i = 0; i <= n; ++i)
+        pos[i] = n + 1;
+    for (int i = n; i >= 0; --i) {
+        nxt[i] = pos[a[i]];
+        pos[a[i]] = i;
+    }
+    int x = 0, y = 0;  // the last elements of the two subarrays
+    int res = 0;
+    for (int z = 1; z <= n; ++z) {
+        // Greedy Strategy I
+        if (a[x] == a[z]) {
+            res += a[y] != a[z];
+            y = z;
+        } else if (a[y] == a[z]) {
+            res += a[x] != a[z];
+            x = z;
+        }
+        // Greedy Strategy II
+        else if (nxt[x] < nxt[y]) {
+            res += a[x] != a[z];
+            x = z;
+        } else {
+            res += a[y] != a[z];
+            y = z;
+        }
+    }
+    printf("%d\n", res);
+}
+
+int main() {
+    solve();
+    return 0;
+}
\ No newline at end of file
diff --git a/paintb.cpp b/paintb.cpp
new file mode 100644
index 0000000..7439dce
--- /dev/null
+++ b/paintb.cpp
@@ -0,0 +1,52 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<ll, ll>;
+using vi = vector<ll>;
+using vpi = vector<pi>;
+using vb = vector<bool>;
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+
+    ll m;
+    cin >> m;
+
+    vi a(m);
+    for(ll i = 0; i < m; i++) {
+        cin >> a[i];
+    }
+
+    auto it = unique(a.begin(), a.end());
+    ll n = distance(a.begin(), it);
+    a.resize(n);
+
+    set<ll> ac;
+
+    ll ans = 0;
+    for (ll i = 0; i < n; i++) {
+        if (i < 2) ac.insert(a[i]);
+    }
+
+    if(ac.size() < 2) {
+        cout << 1 << endl;
+        return 0;
+    }
+
+    ans = 2;
+
+    for (ll i = 2; i < n; i++) {
+        if(ac.find(a[i]) != ac.end()) {
+            ac.clear();
+            ac.insert(a[i - 1]);
+        } else
+            ans++;
+        ac.insert(a[i]);
+    }
+
+    cout << ans << endl;
+
+    return 0;
+}
\ No newline at end of file
diff --git a/playlist.cpp b/playlist.cpp
new file mode 100644
index 0000000..e762934
--- /dev/null
+++ b/playlist.cpp
@@ -0,0 +1,78 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+using ll = long long;
+using pi = pair<ll, ll>;
+using vi = vector<ll>;
+using vpi = vector<pi>;
+using vb = vector<bool>;
+
+ll gcd(ll a, ll b) {
+    if (b == 0)
+        return a;
+    return gcd(b, a % b);
+}
+
+void solve() {
+    ll n;
+    cin >> n;
+
+    vi a(n);
+
+    priority_queue<pi> pq;
+    set<ll> s;
+
+    for (ll i = 0; i < n; i++) {
+        cin >> a[i];
+        s.insert(i);
+    }
+
+    for (ll i = 0; i < n; i++) {
+        if (gcd(a[i], a[(i + 1) % n]) == 1) pq.push({-i, i});
+    }
+
+    vi path;
+
+    while (!pq.empty()) {
+        if (s.size() <= 1) {
+            path.push_back(*s.begin() + 1);
+            break;
+        }
+        pi top = pq.top();
+        pq.pop();
+
+        ll v = a[top.second];
+
+        auto it = next(s.find(top.second));
+        if (it == s.end()) it = s.begin();
+        if (!pq.empty()) {
+            pi nxt = pq.top();
+            if (nxt.second == *it) pq.pop();
+        }
+        auto it2 = it;
+        it = next(it);
+        if (it == s.end()) it = s.begin();
+        if (gcd(v, a[*it]) == 1) pq.push({top.first - n, top.second});
+        path.push_back(*it2 + 1);
+        s.erase(it2);
+    }
+
+    cout << path.size() << " ";
+
+    for (ll i : path) {
+        cout << i << " ";
+    }
+
+    cout << endl;
+}
+
+int main() {
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+
+    ll t;
+    cin >> t;
+    while (t--) solve();
+
+    return 0;
+}
\ No newline at end of file
diff --git a/reconperm.cpp b/reconperm.cpp
new file mode 100644
index 0000000..6a6db04
--- /dev/null
+++ b/reconperm.cpp
@@ -0,0 +1,39 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+using ll = int;
+using pi = pair<ll, ll>;
+using vi = vector<ll>;
+using vpi = vector<pi>;
+using vb = vector<bool>;
+
+class ReconstructPermutation {
+    public:
+    vector<int> reconstruct(int n, vector<int> partial) {
+        set<ll> left;
+        for(int i = 0; i < n; i++) {
+            left.insert(i);
+        }
+
+        for(int i : partial) {
+            left.erase(i);
+        }
+
+        int j = 0;
+        int k = 0;
+        vi path(n, -1);
+        for (int i : left) {
+            cout << i << endl;
+            if (j == partial.size() || i < partial[j]) {
+                path[k++] = i;
+                continue;
+            }
+            while(!(i < partial[j])) {
+                path[k++] = partial[j++];
+                if (j == partial.size()) break;
+            }
+        }
+
+        return path;
+    }
+};
\ No newline at end of file
diff --git a/struct.cpp b/struct.cpp
index 047e177..5d229b0 100644
--- a/struct.cpp
+++ b/struct.cpp
@@ -35,5 +35,4 @@ int main() {
     a.x;
 
     return 0;
-}
-
+}
\ No newline at end of file