A - Teams Forming

.本题就是先进行排序然后将其两两做差求和即可

#include<iostream>
using namespace std;
//交换
void swap(int list[], int left, int right) {
	int tamp;
	tamp = list[left];
	list[left] = list[right];
	list[right] = tamp;
}
//求分割点
int qiupoint(int list[], int left, int right) {
	int frist = list[left];
	while (left < right) {
		while (left < right&&list[right]>=frist) {
			right--;
		}
		swap(list, left, right);
		while (left < right&&list[left]<=frist) {
			left++;
		}
		swap(list, left, right);



	}

	return left;
}

//快速排序法
void quickpx(int list[], int left, int right) {
	if (left < right) {
		//分割点
		int point = qiupoint(list, left, right);
		//递归左调用
		quickpx(list, left, point - 1);
		//递归右调用
		quickpx(list, point + 1, right);


	}


}




int main() {

int n;
	cin >> n;
	const int h = n;
	if (2 <= n && n <= 100 && n % 2 == 0) {
		int list[1000];
		for (int i = 0; i < n; ++i) {
			cin >> list[i];
		}
		quickpx(list, 0, n - 1);
		int sum=0;
		for (int i = 0; i < n; i+=2) {
			sum = sum + (list[i + 1] - list[i]);
		}
		cout << sum << endl;


	}



	return 0;
}