大佬们 八十四分是为什么啊啊啊啊啊 code：

#include <iostream>
#include <cmath>
#include <algorithm> 
using namespace std;

int n, a[100010];
int cc;
int ans;

int main(){
	int x, y;
	int up = 0;
	int down = 0;
	cin >> n;
	for(int i = 1; i <= n; i++){
		cin >> x >> y;
		up += x;
		down += y;
		a[i] = x - y;
	}
	cc = down - up;
	sort(a + 1, a + n + 1);
	if(cc == 0){
		cout << 0;
		return 0;
	}
	else if(cc < 0){
		for(int i = n; i >= 1; i--){
			if(a[i] > 0 && cc + 2 * a[i] <= 0){
				cc += 2 * a[i];
				ans ++;
			}
		}
	}
	else{
		for(int i = 1; i <= n; i++){
			if(a[i] < 0 && cc + 2 * a[i] >= 0){
				cc += 2 * a[i];
				ans ++;
			}
		}
	}
	cout << ans;
	return 0;
}