vault backup: 2022-07-10 09:57:15

OJ notes/pages/Leetcode Rotate-Array.md

@@ -58,6 +58,41 @@ rotate 2 steps to the right: [3,99,-1,-100]
 
 #### Method 2: Copy
 
+Watch out for integer overflow.
+
 #### Method 3: CPP's STL
 
+
+
 ### Solution
+
+Method 2:
+```cpp
+class Solution {
+  void swap(vector<int> &nums, int l, int r) {
+    int temp = nums[l];
+    nums[l] = nums[r];
+    nums[r] = temp;
+  }
+
+public:
+  void rotate(vector<int> &nums, int k) {
+    int size = nums.size();
+    if (size <= 1) {
+      return;
+    }
+    // Copy
+    k = size - k;
+    while (k < 0) {
+      k += size;
+    }
+    vector<int> ans(nums.size());
+    for (int i = 0; i < size; i++) {
+      ans[i] = nums[(i + k) % size];
+    }
+    for (int i = 0; i < size; i++) {
+      nums[i] = ans[i];
+    }
+  }
+};
+```