SPOJ/TOE2

SPOJ/TOE2.cc

@@ -0,0 +1,74 @@
+#include <iostream>
+#include <vector>
+#include <string>
+#include <queue>
+#include <utility>
+#include <map>
+
+using namespace std;
+
+bool check_row(string s) {
+    if(s[0] == '.') return false;
+    return s == string(3, s[0]);
+}
+
+bool check_main_d(vector<string>& v) {
+    if(v[0][0] == '.') return false;
+    return v[0][0] == v[1][1] && v[1][1] == v[2][2];
+}
+
+bool check_second_d(vector<string>& v) {
+    if(v[2][0] == '.') return false;
+    return v[2][0] == v[1][1] && v[1][1] == v[0][2];
+}
+
+bool check_column(vector<string>& v, int c) {
+    if(v[0][c] == '.') return false;
+    return v[0][c] == v[1][c] && v[1][c] == v[2][c];
+}
+
+bool has_ended(string s) {
+    bool b = true;
+    for(auto c : s) {
+        if(c == '.') { b = false; break; }
+    }
+    if(b) return true;
+    vector<string> v = {s.substr(0, 3), s.substr(3, 3), s.substr(6, 3)};
+    for(auto r : v) {
+        if(check_row(r)) return true;
+    }
+    for(int i = 0; i < 3; ++i) {
+        if(check_column(v, i)) return true;
+    }
+    if(check_main_d(v)) return true;
+    if(check_second_d(v)) return true;
+    return false;
+}
+
+void check(string board) {
+    string ans = "invalid";
+    map<bool, char> plays = {{true, 'X'}, {false, 'O'}};
+    queue<pair<string, bool>> q;
+    q.push({".........", true});
+    while(q.size()) {
+        auto [s, b] = q.front();
+        q.pop();
+        if(s == board) { ans = "valid"; break; }
+        if(has_ended(s)) continue;
+        for(int i = 0; i < 9; ++i) {
+            if(s[i] != '.') continue;
+            auto tmp = s;
+            tmp[i] = plays[b];
+            if(tmp[i] == board[i]) q.push({tmp, !b});
+        }
+    }
+    cout << ans << endl;
+}
+
+int main() {
+    string board;
+    while(cin >> board, board != "end") {
+        if(has_ended(board)) { check(board); }
+        else { cout << "invalid" << endl; }
+    }
+}