[leetcode]72. Edit Distance(Java)

https://leetcode.com/problems/edit-distance/#/description

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

package go.jacob.day708;

/**
* 72. Edit Distance
* @author Jacob
*
*/
public class Demo3 {
/*
* 动态规划应用
*/
public int minDistance(String word1, String word2) {
if (word1 == null || word2 == null)
return 0;
int[][] res = new int[word1.length() + 1][word2.length() + 1];
for (int i = 0; i <= word1.length(); i++) {
res[i][0] = i;
}
for (int j = 0; j <= word2.length(); j++) {
res[0][j] = j;
}

for (int i = 0; i < word1.length(); i++) {
for (int j = 0; j < word2.length(); j++) {
if (word1.charAt(i) == word2.charAt(j))
res[i + 1][j + 1] = res[i][j];
else {
res[i + 1][j + 1] = 1 + min(res[i + 1][j], res[i][j + 1], res[i][j]);
}
}
}

return res[word1.length()][word2.length()];
}

private int min(int i, int j, int k) {
int min = Math.min(i, j);
min = Math.min(min, k);
return min;
}

}