9252 gap-LCA trace

baekjoon/9252_LCS2.cpp

@@ -0,0 +1,80 @@
+#include <iostream>
+#include <vector>
+#include <string>
+#include <stack>
+
+using namespace std;
+
+int N, M;
+string str1, str2;
+vector<vector<int>> vv_DP;
+vector<vector<pair<int, int>>> vv_trace;
+
+string getString()
+{
+    stack<char> s_LCS;
+    string LCS;
+    auto current = make_pair(N, M);
+    while (current.first > 0 && current.second > 0)
+    {
+        auto next = vv_trace[current.first][current.second];
+        if (current.first != next.first && current.second != next.second)
+            s_LCS.push(str1[current.first - 1]);
+        current = next;
+    }
+    while (!s_LCS.empty())
+    {
+        LCS += s_LCS.top();
+        s_LCS.pop();
+    }
+    return LCS;
+}
+
+void solution()
+{
+    cin >> str1 >> str2;
+    N = str1.size();
+    M = str2.size();
+
+    vv_DP.resize(N + 1);
+    vv_trace.resize(N + 1);
+    for (int i = 0; i <= N; i++)
+    {
+        vv_DP[i].resize(str2.size() + 1);
+        vv_trace[i].resize(str2.size() + 1);
+    }
+
+    for (int row = 1; row <= N; row++)
+    {
+        for (int col = 1; col <= M; col++)
+        {
+            if (vv_DP[row - 1][col] > vv_DP[row][col - 1])
+            {
+                vv_DP[row][col] = vv_DP[row - 1][col];
+                vv_trace[row][col] = make_pair(row - 1, col);
+            }
+            else
+            {
+                vv_DP[row][col] = vv_DP[row][col - 1];
+                vv_trace[row][col] = make_pair(row, col - 1);
+            }
+            if (str1[row - 1] == str2[col - 1] && vv_DP[row][col] < vv_DP[row - 1][col - 1] + 1)
+            {
+                vv_DP[row][col] = max(vv_DP[row][col], vv_DP[row - 1][col - 1] + 1);
+                vv_trace[row][col] = make_pair(row - 1, col - 1);
+            }
+        }
+    }
+    string LCS = getString();
+    cout << vv_DP[N][M] << "\n";
+    if (vv_DP[N][M] > 0)
+        cout << LCS << "\n";
+}
+
+int main()
+{
+    ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    solution();
+    return 0;
+}