2 条题解
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0
以下是询问chatGPT得到的Accepted答案
#include <vector> using namespace std; long long merge(vector<int>& nums, int left, int mid, int right) { vector<int> tmp(right - left + 1); int i = left, j = mid + 1, k = 0; long long count = 0; while (i <= mid && j <= right) { if (nums[i] <= nums[j]) { tmp[k++] = nums[i++]; } else { tmp[k++] = nums[j++]; count += mid - i + 1; } } while (i <= mid) { tmp[k++] = nums[i++]; } while (j <= right) { tmp[k++] = nums[j++]; } for (k = 0, i = left; i <= right; ++i, ++k) { nums[i] = tmp[k]; } return count; } long long merge_sort(vector<int>& nums, int left, int right) { if (left >= right) { return 0; } int mid = (left + right) >> 1; long long count_left = merge_sort(nums, left, mid); long long count_right = merge_sort(nums, mid + 1, right); long long count = merge(nums, left, mid, right); return count_left + count_right + count; } int main() { int n; cin >> n; vector<int> nums(n); for (int i = 0; i < n; ++i) { cin >> nums[i]; } cout << merge_sort(nums, 0, n - 1) << endl; return 0; }
信息
- ID
- 435
- 时间
- 1000ms
- 内存
- 256MiB
- 难度
- 6
- 标签
- 递交数
- 70
- 已通过
- 23
- 上传者