feat: update solutions to lcof problems

- 面试题03. 数组中重复的数字
- 面试题53 - I. 在排序数组中查找数字 I
- 面试题53 - II. 0～n-1中缺失的数字

Author: YangFong

lcof/面试题03. 数组中重复的数字/README.md

@@ -177,10 +177,10 @@ impl Solution {
     pub fn find_repeat_number(mut nums: Vec<i32>) -> i32 {
         for i in 0..nums.len() {
             while i as i32 != nums[i] {
-                if nums[i] == nums[nums[i] as usize] {
+                let j = nums[i] as usize;
+                if nums[i] == nums[j] {
                     return nums[i];
                 }
-                let j = nums[i] as usize;
                 nums.swap(i, j);
             }
         }

lcof/面试题03. 数组中重复的数字/Solution.rs

@@ -2,10 +2,10 @@ impl Solution {
     pub fn find_repeat_number(mut nums: Vec<i32>) -> i32 {
         for i in 0..nums.len() {
             while i as i32 != nums[i] {
-                if nums[i] == nums[nums[i] as usize] {
+                let j = nums[i] as usize;
+                if nums[i] == nums[j] {
                     return nums[i];
                 }
-                let j = nums[i] as usize;
                 nums.swap(i, j);
             }
         }

lcof/面试题53 - I. 在排序数组中查找数字 I/README.md

@@ -216,39 +216,21 @@ var search = function (nums, target) {
 ```rust
 impl Solution {
     pub fn search(nums: Vec<i32>, target: i32) -> i32 {
-        fn my_search(nums: &Vec<i32>, target: i32, left: i32, right: i32) -> i32 {
-            if left > right {
-                return 0;
-            }
-
-            let index = (right - left) / 2 + left;
-            let num = nums[index as usize];
-            if num > target {
-                my_search(nums, target, left, index - 1)
-            } else if num < target {
-                my_search(nums, target, index + 1, right)
-            } else {
-                // 搜索边界
-                let mut count = 1;
-                for i in (0..index).rev() {
-                    if nums[i as usize] == target {
-                        count += 1;
-                    } else {
-                        break;
-                    }
+        let help = |target| {
+            let mut left = 0;
+            let mut right = nums.len();
+            while left < right  {
+                let mid = left + (right - left) / 2;
+                if nums[mid] <= target {
+                    left = mid + 1;
+                } else {
+                    right = mid;
                 }
-                for i in (index + 1)..nums.len() as i32  {
-                    if nums[i as usize] == target {
-                        count += 1;
-                    } else {
-                        break;
-                    }
-                }
-                count
             }
-        }
+            left as i32
+        };
 
-        my_search(&nums, target, 0, nums.len() as i32 - 1)
+        help(target) - help(target - 1)
     }
 }
 ```

lcof/面试题53 - I. 在排序数组中查找数字 I/Solution.rs

@@ -1,37 +1,19 @@
 impl Solution {
     pub fn search(nums: Vec<i32>, target: i32) -> i32 {
-        fn my_search(nums: &Vec<i32>, target: i32, left: i32, right: i32) -> i32 {
-            if left > right {
-                return 0;
-            }
-
-            let index = (right - left) / 2 + left;
-            let num = nums[index as usize];
-            if num > target {
-                my_search(nums, target, left, index - 1)
-            } else if num < target {
-                my_search(nums, target, index + 1, right)
-            } else {
-                // 搜索边界
-                let mut count = 1;
-                for i in (0..index).rev() {
-                    if nums[i as usize] == target {
-                        count += 1;
-                    } else {
-                        break;
-                    }
-                }
-                for i in (index + 1)..nums.len() as i32 {
-                    if nums[i as usize] == target {
-                        count += 1;
-                    } else {
-                        break;
-                    }
+        let help = |target| {
+            let mut left = 0;
+            let mut right = nums.len();
+            while left < right  {
+                let mid = left + (right - left) / 2;
+                if nums[mid] <= target {
+                    left = mid + 1;
+                } else {
+                    right = mid;
                 }
-                count
             }
-        }
+            left as i32
+        };
 
-        my_search(&nums, target, 0, nums.len() as i32 - 1)
+        help(target) - help(target - 1)
     }
-}
+}

lcof/面试题53 - II. 0～n-1中缺失的数字/README.md

@@ -116,6 +116,36 @@ public:
 };
 ```
 
+### **Rust**
+
+```rust
+impl Solution {
+    pub fn missing_number(nums: Vec<i32>) -> i32 {
+        let n = nums.len() as i32;
+        let mut sum = (1 + n) * n / 2;
+        for num in nums.iter() {
+            sum -= num;
+        }
+        sum
+    }
+}
+```
+
+```rust
+impl Solution {
+    pub fn missing_number(nums: Vec<i32>) -> i32 {
+        let mut prev = 0;
+        for &num in nums.iter() {
+            if prev != num {
+                return prev;
+            }
+            prev += 1;
+        }
+        prev
+    }
+}
+```
+
 ### **...**
 
 ```

lcof/面试题53 - II. 0～n-1中缺失的数字/Solution.rs

@@ -0,0 +1,12 @@
+impl Solution {
+    pub fn missing_number(nums: Vec<i32>) -> i32 {
+        let mut prev = 0;
+        for &num in nums.iter() {
+            if prev != num {
+                return prev;
+            }
+            prev += 1;
+        }
+        prev
+    }
+}