Difficulty: Hard
Given two words word1 and word2, find the minimum number of operations required to convert word1 to word2.
You have the following 3 operations permitted on a word:
- Insert a character
- Delete a character
- Replace a character
Example 1:
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| Input: word1 = "horse", word2 = "ros"
Output: 3
Explanation:
horse -> rorse (replace 'h' with 'r')
rorse -> rose (remove 'r')
rose -> ros (remove 'e')
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Example 2:
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| Input: word1 = "intention", word2 = "execution"
Output: 5
Explanation:
intention -> inention (remove 't')
inention -> enention (replace 'i' with 'e')
enention -> exention (replace 'n' with 'x')
exention -> exection (replace 'n' with 'c')
exection -> execution (insert 'u')
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Solution
Language: Java
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| class Solution {
public int minDistance(String word1, String word2) {
if (word1 == null || word2 == null) {
return 0;
}
int m = word1.length();
int n = word2.length();
int[][] dp = new int[m + 1][n + 1];
for (int i = 0; i <= n; i++) {
dp[0][i] = i;
}
for (int j = 1; j <= m; j++) {
dp[j][0] = j;
}
for (int i = 1; i <= m; i++) {
for (int j = 1; j <= n; j++) {
if (word1.charAt(i - 1) == word2.charAt(j - 1)) {
dp[i][j] = Math.min(dp[i - 1][j - 1], Math.min(dp[i - 1][j], dp[i][j - 1]) + 1);
} else {
dp[i][j] = Math.min(dp[i - 1][j - 1], Math.min(dp[i - 1][j], dp[i][j - 1])) + 1;
}
}
}
return dp[m][n];
}
}
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