Levenshtein distance

#include <cstdio>
#include <vector>
#include <iostream>
using namespace std;
int main()
{
    string s, t;
    cin >> s >> t;
    int n = s.length(), m = t.length(), i, j;
    vector < vector <int> > dp(n, vector <int> (m));
    if(s[0] != t[0]) dp[0][0] = 1;
    for(i = 1; i < n; i++) dp[i][0] = i;
    for(j = 1; j < m; j++) dp[0][j] = j;
    for(i = 1; i < n; i++) for(j = 1; j < m; j++) dp[i][j] = min(dp[i - 1][j] + 1, min(dp[i][j - 1] + 1, dp[i - 1][j - 1] + ((s[i] != t[j]) ? 1 : 0)));
    printf("%d", dp[n - 1][m - 1]);
    return 0;
}