72. Edit Distance

Edit Distance

Given two words word1 and word2, find the minimum number of steps required to convert word1 to word2. (each operation is counted as 1 step.)

You have the following 3 operations permitted on a word:

a) Insert a character b) Delete a character c) Replace a character

Solution

public class Solution {
    public int minDistance(String word1, String word2) {
            int m = word1.length();
        int n = word2.length();

        int[][] result = new int[m+1][n+1];
        for(int i = 0; i <= m; i ++) result[i][0] = i;
        for(int i = 0; i <= n; i ++) result[0][i] = i;

        for(int i = 1; i <= m; i ++) {
            for(int j = 1; j <= n; j ++) {
                int min = Math.min(result[i][j-1]+1, result[i-1][j]+1);

                if (word1.charAt(i-1) == word2.charAt(j-1)) {
                    min = Math.min(min, result[i-1][j-1]);
                } else {
                    min = Math.min(min, result[i-1][j-1] + 1);
                }

                result[i][j] = min;
            }
        }

        return result[m][n];
    }
}