```
public class Solution {
public int minDistance(String s, String t) {
int m = s.length(), n = t.length();
int[][] f = new int[m+1][n+1];
for (int i = 1; i <= m; i++)
Arrays.fill(f[i], Integer.MAX_VALUE);
for (int i = 0; i <= n; i++)
f[0][i] = i;
for (int i = 0; i <= m; i++)
f[i][0] = i;
for (int i = 0; i < m; i++)
for (int j = 0; j < n; j++)
if (s.charAt(i) == t.charAt(j))
f[i+1][j+1] = Math.min(f[i][j], f[i+1][j+1]);
else
f[i+1][j+1] = Math.min(Math.min(f[i][j]+1, Math.min(f[i+1][j]+1, f[i][j+1]+1)), f[i+1][j+1]);
return f[m][n];
}
}
```