Update 1143.最长公共子序列.md about rust

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
+impl Solution {
     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
+        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 {
-                last[j].max(dp[j - 1])
-            };
+                    dp[i + 1][j + 1] = dp[i][j + 1].max(dp[i + 1][j]);
                 }
             }
-    dp[m]
+        }
+        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()]
+    }
 }
 ```