feat: add rust solution to lc problem: No.0042 (#1313)

* feat: add rust solution to lc problem: No.0042

* feat: add rust solution to lc problem: No.0042

Author: xzhseh

solution/0000-0099/0042.Trapping Rain Water/README.md

@@ -113,6 +113,37 @@ public:
 };
 ```
 
+### **Rust**
+
+```rust
+impl Solution {
+    #[allow(dead_code)]
+    pub fn trap(height: Vec<i32>) -> i32 {
+        let n = height.len();
+        let mut left: Vec<i32> = vec![0; n];
+        let mut right: Vec<i32> = vec![0; n];
+
+        left[0] = height[0];
+        right[n - 1] = height[n - 1];
+
+        // Initialize the left & right vector
+        for i in 1..n {
+            left[i] = std::cmp::max(left[i - 1], height[i]);
+            right[n - i - 1] = std::cmp::max(right[n - i], height[n - i - 1]);
+        }
+
+        let mut ans = 0;
+
+        // Calculate the ans
+        for i in 0..n {
+            ans += std::cmp::min(left[i], right[i]) - height[i];
+        }
+
+        ans
+    }
+}
+```
+
 ### **Go**
 
 ```go

solution/0000-0099/0042.Trapping Rain Water/README_EN.md

@@ -101,6 +101,37 @@ public:
 };
 ```
 
+### **Rust**
+
+```rust
+impl Solution {
+    #[allow(dead_code)]
+    pub fn trap(height: Vec<i32>) -> i32 {
+        let n = height.len();
+        let mut left: Vec<i32> = vec![0; n];
+        let mut right: Vec<i32> = vec![0; n];
+
+        left[0] = height[0];
+        right[n - 1] = height[n - 1];
+
+        // Initialize the left & right vector
+        for i in 1..n {
+            left[i] = std::cmp::max(left[i - 1], height[i]);
+            right[n - i - 1] = std::cmp::max(right[n - i], height[n - i - 1]);
+        }
+
+        let mut ans = 0;
+
+        // Calculate the ans
+        for i in 0..n {
+            ans += std::cmp::min(left[i], right[i]) - height[i];
+        }
+
+        ans
+    }
+}
+```
+
 ### **Go**
 
 ```go

solution/0000-0099/0042.Trapping Rain Water/Solution.rs

@@ -0,0 +1,26 @@
+impl Solution {
+    #[allow(dead_code)]
+    pub fn trap(height: Vec<i32>) -> i32 {
+        let n = height.len();
+        let mut left: Vec<i32> = vec![0; n];
+        let mut right: Vec<i32> = vec![0; n];
+
+        left[0] = height[0];
+        right[n - 1] = height[n - 1];
+
+        // Initialize the left & right vector
+        for i in 1..n {
+            left[i] = std::cmp::max(left[i - 1], height[i]);
+            right[n - i - 1] = std::cmp::max(right[n - i], height[n - i - 1]);
+        }
+
+        let mut ans = 0;
+
+        // Calculate the ans
+        for i in 0..n {
+            ans += std::cmp::min(left[i], right[i]) - height[i];
+        }
+
+        ans
+    }
+}