Merge pull request #2241 from fwqaaq/master-2

Update 0496.下一个更大元素I.md 优化 rust

problems/0496.下一个更大元素I.md

@@ -396,25 +396,33 @@ function nextGreaterElement(nums1: number[], nums2: number[]): number[] {
 ### Rust
 
 ```rust
+use std::collections::HashMap;
 impl Solution {
     pub fn next_greater_element(nums1: Vec<i32>, nums2: Vec<i32>) -> Vec<i32> {
-        let mut ans = vec![-1; nums1.len()];
-        use std::collections::HashMap;
-        let mut map = HashMap::new();
-        for (idx, &i) in nums1.iter().enumerate() {
-            map.insert(i, idx);
+        let (mut res, mut map) = (vec![-1; nums1.len()], HashMap::new());
+        if nums1.is_empty() {
+            return res;
         }
+
+        nums1.into_iter().enumerate().for_each(|(v, k)| {
+            map.insert(k, v);
+        });
+
         let mut stack = vec![];
-        for (idx, &i) in nums2.iter().enumerate() {
-            while !stack.is_empty() && nums2[*stack.last().unwrap()] < i {
-                let pos = stack.pop().unwrap();
-                if let Some(&jdx) = map.get(&nums2[pos]) {
-                    ans[jdx] = i;
+        for (i, &value) in nums2.iter().enumerate() {
+            while let Some(&top) = stack.last() {
+                if value <= nums2[top] {
+                    break;
+                }
+                let stacked_index = stack.pop().unwrap();
+                if let Some(&mapped_index) = map.get(&nums2[stacked_index]) {
+                    res[mapped_index] = value;
                 }
             }
-            stack.push(idx);
+            stack.push(i);
         }
-        ans
+
+        res
     }
 }
 ```