和T583可以说是一模子里出来的
class Solution {
public int minDistance(String word1, String word2) {
int len1 = word1.length(), len2 = word2.length();
int[][] dp = new int[len1 + 1][len2 + 1];
// word1字符串为空时,word2字符全删
for(int i = 0; i <= len1; i++) dp[i][0] = i;
// word2字符串为空时,word1字符全删
for(int i = 0; i <= len2; i++) dp[0][i] = i;
for (int i = 1; i <= len1; i++) {
for (int j = 1; j <= len2; j++) {
if (word1.charAt(i - 1) == word2.charAt(j - 1)) {
dp[i][j] = dp[i - 1][j - 1];
} else {
// word2添加一个元素,相当于word1删除一个元素
// word1删除:dp[i][j] = dp[i - 1][j] + 1
// word2删除:dp[i][j] = dp[i][j - 1] + 1
// 替换:dp[i][j] = dp[i - 1][j - 1] + 1
dp[i][j] = Math.min(Math.min(dp[i - 1][j - 1], dp[i][j - 1]), dp[i - 1][j]) + 1;
}
}
}
return dp[len1][len2];
}
}