check-if-n-and-its-double-exist

Author: bestgopher

README.md

@@ -2,7 +2,12 @@
 leetcode by rust
 
 ### 题目
+
+- [746. 使用最小花费爬楼梯]
+	- [src](https://github.com/rustors/leetcode/blob/main/src/bin/check-if-n-and-its-double-exist.rs) 
+	- [leetcode](https://leetcode-cn.com/problems/check-if-n-and-its-double-exist/)
+
 - 1008：前序遍历构造二叉搜索树
-    - [src](https://github.com/rustors/leetcode/blob/main/src/bin/construct-binary-search-tree-from-preorder-traversal.rs)
-    - [leetcode](https://leetcode-cn.com/problems/construct-binary-search-tree-from-preorder-traversal/)
+- [src](https://github.com/rustors/leetcode/blob/main/src/bin/construct-binary-search-tree-from-preorder-traversal.rs)
+	- [leetcode](https://leetcode-cn.com/problems/construct-binary-search-tree-from-preorder-traversal/)
 

src/bin/check-if-n-and-its-double-exist.rs

@@ -0,0 +1,23 @@
+fn main() {}
+
+struct Solution;
+
+impl Solution {
+    pub fn check_if_exist(arr: Vec<i32>) -> bool {
+        let mut map = std::collections::HashMap::<i32, usize>::new();
+
+        for (index, value) in arr.iter().enumerate() {
+            map.insert(*value, index);
+        }
+
+        for (index, value) in arr.iter().map(|x| x * 2).enumerate() {
+            if let Some(i) = map.get(&value) {
+                if *i != index {
+                    return true;
+                }
+            }
+        }
+
+        false
+    }
+}