Leetcode 72. Edit Distance

Question

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

Code

/*
动态规划算法解决
*/
public int minDistance(String word1, String word2) {
if (word1.length() == 0 || word2.length() == 0) {
return word1.length() == 0 ? word2.length() : word1.length();
}
int[][] weights = new int[word1.length() + 1][word2.length() + 1];

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