1143. Longest Common Subsequence - medium
문제
Given two strings text1 and text2, return the length of their longest common subsequence.
A subsequence of a string is a new string generated from the original string with some characters(can be none) deleted without changing the relative order of the remaining characters. (eg, “ace” is a subsequence of “abcde” while “aec” is not). A common subsequence of two strings is a subsequence that is common to both strings.
If there is no common subsequence, return 0.
제한사항
- 1 <= text1.length <= 1000
- 1 <= text2.length <= 1000
- The input strings consist of lowercase English characters only.
입출력 예
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Example 1:
Input: text1 = "abcde", text2 = "ace"
Output: 3
Explanation: The longest common subsequence is "ace" and its length is 3.
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Example 2:
Input: text1 = "abc", text2 = "abc"
Output: 3
Explanation: The longest common subsequence is "abc" and its length is 3.
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Example 3:
Input: text1 = "abc", text2 = "def"
Output: 0
Explanation: There is no such common subsequence, so the result is 0.
풀이
- DP
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func longestCommonSubsequence(text1 string, text2 string) int {
grid := make([][]int, len(text1)+1)
for i := 0 ; i <= len(text1) ; i++ {
grid[i] = make([]int, len(text2)+1)
}
for m := 1 ; m <= len(text1) ; m++ {
for n := 1 ; n <= len(text2) ; n++ {
if text1[m-1] == text2[n-1] {
grid[m][n] = grid[m-1][n-1] + 1
} else {
if grid[m-1][n] >= grid[m][n-1] {
grid[m][n] = grid[m-1][n]
} else {
grid[m][n] = grid[m][n-1]
}
}
}
}
return grid[len(text1)][len(text2)]
}