Update 0121.买卖股票的最佳时机.md about rust

problems/0121.买卖股票的最佳时机.md

@@ -510,7 +510,22 @@ public class Solution
 }
 ```
 
+Rust:
 
+> 贪心
+
+```rust
+impl Solution {
+    pub fn max_profit(prices: Vec<i32>) -> i32 {
+        let (mut low, mut res) = (i32::MAX, 0);
+        for p in prices {
+            low = p.min(low);
+            res = res.max(p - low);
+        }
+        res
+    }
+}
+```
 
 
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