Chapter 3 : HARD Problem

E : LCS
Diff : Hard(7)
Code :

#include <bits/stdc++.h>
using namespace std;

int LCS(string a, string b) {
    int f[a.length()+1][b.length()+1];
    for (int i=0;i<=a.length();i++) {
        for (int j=0;j<=b.length();j++) {
            if (i==0||j==0) f[i][j] = 0;
            else if (a[i-1]==b[j-1]) f[i][j] = f[i-1][j-1] + 1;
            else f[i][j] = max(f[i-1][j], f[i][j-1]);
        }
    }
    return f[a.length()][b.length()];
}

int main() {
    string a, b;
    while(cin >> a >> b) cout << LCS(a, b) << endl;
    return 0;
}

Comment :
Before : WHAT THE **
After : OH, a friendly DP.