Update 0072.编辑距离.md

problems/0072.编辑距离.md

@@ -429,6 +429,36 @@ impl Solution {
 }
 ```
 
+> 一维 dp
+
+```rust
+impl Solution {
+    pub fn min_distance(word1: String, word2: String) -> i32 {
+        let mut dp = vec![0; word1.len() + 1];
+        for (i, v) in dp.iter_mut().enumerate().skip(1) {
+            *v = i;
+        }
+
+        for char2 in word2.chars() {
+            // 相当于 dp[i][0] 的初始化
+            let mut pre = dp[0];
+            dp[0] += 1; // j = 0, 将前 i 个字符变成空串的个数
+            for (j, char1) in word1.chars().enumerate() {
+                let temp = dp[j + 1];
+                if char1 == char2 {
+                    dp[j + 1] = pre;
+                } else {
+                    dp[j + 1] = dp[j + 1].min(dp[j]).min(pre) + 1;
+                }
+                pre = temp;
+            }
+        }
+
+        dp[word1.len()] as i32
+    }
+}
+```
+
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