LeetCode-in-All
72. Edit Distance
Hard
Given two strings word1 and word2, return the minimum number of operations required to convert word1 to word2.
You have the following three operations permitted on a word:
- Insert a character
- Delete a character
- Replace a character
Example 1:
Input: word1 = “horse”, word2 = “ros”
Output: 3
Explanation:
horse -> rorse (replace ‘h’ with ‘r’)
rorse -> rose (remove ‘r’)
rose -> ros (remove ‘e’)
Example 2:
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’)
Constraints:
0 <= word1.length, word2.length <= 500word1andword2consist of lowercase English letters.
Solution
func minDistance(word1 string, word2 string) int {
n1 := len(word1)
n2 := len(word2)
if n2 > n1 {
return minDistance(word2, word1)
}
dp := make([]int, n2+1)
for j := 0; j <= n2; j++ {
dp[j] = j
}
for i := 1; i <= n1; i++ {
prev := dp[0]
dp[0] = i
for j := 1; j <= n2; j++ {
temp := dp[j]
if word1[i-1] != word2[j-1] {
dp[j] = 1 + min(prev, min(dp[j], dp[j-1]))
} else {
dp[j] = prev
}
prev = temp
}
}
return dp[n2]
}
func min(x, y int) int {
if x < y {
return x
}
return y
}