public class Solution {
public int minDistance(String word1, String word2) {
int n = word1.length();
int m = word2.length();
int[][] f = new int[n + 1][m + 1];
for (int i = 0; i <= n; i++) {
f[i][0] = i;
}
for (int j = 0; j <= m; j++) {
f[0][j] = j;
}
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
if (word1.charAt(i - 1) == word2.charAt(j - 1)) {
f[i][j] = f[i - 1][j - 1];
} else {
f[i][j] = Math.min(f[i - 1][j], Math.min(f[i][j - 1], f[i - 1][j - 1])) + 1;
}
}
}
return f[n][m];
}
}