Merge pull request #1928 from fwqaaq/patch-8

Update 0376.摆动序列.md about rust

problems/0376.摆动序列.md

@@ -462,21 +462,43 @@ var wiggleMaxLength = function(nums) {
 ```Rust
 impl Solution {
     pub fn wiggle_max_length(nums: Vec<i32>) -> i32 {
-        let len = nums.len() as usize;
-        if len <= 1 {
-            return len as i32;
+        if nums.len() == 1 {
+            return 1;
         }
-        let mut preDiff = 0;
-        let mut curDiff = 0;
-        let mut result = 1;
-        for i in 0..len-1 {
-            curDiff = nums[i+1] - nums[i];
-            if (preDiff <= 0 && curDiff > 0) || (preDiff >= 0 && curDiff < 0) {
-                result += 1;
-                preDiff = curDiff;
+        let mut res = 1;
+        let mut pre_diff = 0;
+        for i in 0..nums.len() - 1 {
+            let cur_diff = nums[i + 1] - nums[i];
+            if (pre_diff <= 0 && cur_diff > 0) || (pre_diff >= 0 && cur_diff < 0) {
+                res += 1;
+                pre_diff = cur_diff;
             }
         }
-        result
+        res
+    }
+}
+```
+
+**动态规划**
+
+```rust
+impl Solution {
+    pub fn wiggle_max_length(nums: Vec<i32>) -> i32 {
+        if nums.len() == 1 {
+            return 1;
+        }
+        let (mut down, mut up) = (1, 1);
+        for i in 1..nums.len() {
+            // i - 1 为峰顶
+            if nums[i] < nums[i - 1] {
+                down = down.max(up + 1);
+            }
+            // i - 1 为峰谷
+            if nums[i] > nums[i - 1] {
+                up = up.max(down + 1);
+            }
+        }
+        down.max(up)
     }
 }
 ```