diff --git a/problems/1143.最长公共子序列.md b/problems/1143.最长公共子序列.md index 68269b87..0bd8b1d6 100644 --- a/problems/1143.最长公共子序列.md +++ b/problems/1143.最长公共子序列.md @@ -327,23 +327,51 @@ function longestCommonSubsequence(text1: string, text2: string): number { ``` Rust: + +二维 dp: + ```rust -pub fn longest_common_subsequence(text1: String, text2: String) -> i32 { - let (n, m) = (text1.len(), text2.len()); - let (s1, s2) = (text1.as_bytes(), text2.as_bytes()); - let mut dp = vec![0; m + 1]; - let mut last = vec![0; m + 1]; - for i in 1..=n { - dp.swap_with_slice(&mut last); - for j in 1..=m { - dp[j] = if s1[i - 1] == s2[j - 1] { - last[j - 1] + 1 - } else { - last[j].max(dp[j - 1]) - }; +impl Solution { + pub fn longest_common_subsequence(text1: String, text2: String) -> i32 { + let mut dp = vec![vec![0; text2.len() + 1]; text1.len() + 1]; + for (i, c1) in text1.chars().enumerate() { + for (j, c2) in text2.chars().enumerate() { + if c1 == c2 { + dp[i + 1][j + 1] = dp[i][j] + 1; + } else { + dp[i + 1][j + 1] = dp[i][j + 1].max(dp[i + 1][j]); + } + } } + dp[text1.len()][text2.len()] + } +} +``` + +二维: + +```rust +impl Solution { + pub fn longest_common_subsequence(text1: String, text2: String) -> i32 { + let mut dp = vec![0; text2.len() + 1]; + for c1 in text1.chars() { + // 初始化 prev + let mut prev = 0; + + for (j, c2) in text2.chars().enumerate() { + let temp = dp[j + 1]; + if c1 == c2 { + // 使用上一次的状态,防止重复计算 + dp[j + 1] = prev + 1; + } else { + dp[j + 1] = dp[j + 1].max(dp[j]); + } + // 使用上一次的状态更新 prev + prev = temp; + } + } + dp[text2.len()] } - dp[m] } ```