记住对称性,记住双swap
class Solution {
public:
vector<int> sortArray(vector<int>& nums) {
sort(nums,0,nums.size()-1);
return nums;
}
void sort(vector<int>& nums, int start, int end){
if(start>=end) return;
int index = rand()%(end-start+1)+start;
swap(nums[start],nums[index]);
int key = nums[start], left = start, right = end;
while(left<right){
while(left<right&&nums[right]>=key) right--;
swap(nums[left],nums[right]);
while(left<right&&nums[left]<=key) left++;
swap(nums[left],nums[right]);
}
sort(nums,start,left-1);
sort(nums,left+1,end);
}
};