Edit Distance.java

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

public int minDistance(String word1, String word2) {
    if (word1.length() == 0 || word2.length() == 0)
	return word1.length() == 0 ? word2.length() : word1.length();
    int[][] arr = new int[word2.length() + 1][word1.length() + 1];
    for (int i = 0; i <= word1.length(); i++) {
        arr[0][i] = 0;
    }
    for (int j = 0; j <= word2.length(); j++) {
        arr[j][0] = 0;
    }
    for (int i = 0; i < word1.length(); i++) {
        for (int j = 0; j < word2.length(); j++) {
            if (word1.charAt(i) == word2.charAt(j)) {
		arr[j][i] = arr[j - 1][i - 1];
	    } else {
	        int dis = Math.min(arr[j - 1][i], arr[j][i - 1]);
	        arr[j][i] = Math.min(arr[j - 1][i - 1], dis) + 1;
	    }
        }
    }
    return arr[word2.length()][word1.length()];
}