class Solution { const int MOD = 1000000007; int count = 0; void mergeSort(vector<int>& nums, int left, int right) { if (left >= right) return; int mid = left + (right - left) / 2; mergeSort(nums, left, mid); mergeSort(nums, mid + 1, right); merge(nums, left, mid, right);//对交叉归并的理解更加重要 ...