feat: add rust solution to lc problem: No.0287 (#1648)

Author: xzhseh

solution/0200-0299/0287.Find the Duplicate Number/README.md

@@ -126,6 +126,33 @@ public:
 };
 ```
 
+### **Rust**
+
+```rust
+impl Solution {
+    #[allow(dead_code)]
+    pub fn find_duplicate(nums: Vec<i32>) -> i32 {
+        let mut left = 0;
+        let mut right = nums.len() - 1;
+
+        while left < right {
+            let mid = (left + right) >> 1;
+            let cnt = nums
+                .iter()
+                .filter(|x| **x <= mid as i32)
+                .count();
+            if cnt > mid {
+                right = mid;
+            } else  {
+                left = mid + 1;
+            }
+        }
+
+        left as i32
+    }
+}
+```
+
 ### **Go**
 
 ```go

solution/0200-0299/0287.Find the Duplicate Number/README_EN.md

@@ -107,6 +107,33 @@ public:
 };
 ```
 
+### **Rust**
+
+```rust
+impl Solution {
+    #[allow(dead_code)]
+    pub fn find_duplicate(nums: Vec<i32>) -> i32 {
+        let mut left = 0;
+        let mut right = nums.len() - 1;
+
+        while left < right {
+            let mid = (left + right) >> 1;
+            let cnt = nums
+                .iter()
+                .filter(|x| **x <= mid as i32)
+                .count();
+            if cnt > mid {
+                right = mid;
+            } else  {
+                left = mid + 1;
+            }
+        }
+
+        left as i32
+    }
+}
+```
+
 ### **Go**
 
 ```go

solution/0200-0299/0287.Find the Duplicate Number/Solution.rs

@@ -0,0 +1,22 @@
+impl Solution {
+    #[allow(dead_code)]
+    pub fn find_duplicate(nums: Vec<i32>) -> i32 {
+        let mut left = 0;
+        let mut right = nums.len() - 1;
+
+        while left < right {
+            let mid = (left + right) >> 1;
+            let cnt = nums
+                .iter()
+                .filter(|x| **x <= mid as i32)
+                .count();
+            if cnt > mid {
+                right = mid;
+            } else  {
+                left = mid + 1;
+            }
+        }
+
+        left as i32
+    }
+}