我是按c程序写的，但是死活ac不了，后面随手换成c++就直接通过了？

#include <stdio.h>
#include <stdlib.h>
#define int long long
#define maxn 2000010
int kun[maxn], hun[maxn], left[maxn], right[maxn];
int anser = 999999999999999, r = 0, l = 214748364, mid;


int sum1[maxn] = {0}, sum2[maxn] = {0};
int n, m, s, x, y, sum;

int check(int x) {
	for (int i = 1; i <= n; i++) {
		if (kun[i] >= x) {
			sum1[i] = sum1[i - 1] + 1;
			sum2[i] = sum2[i - 1] + hun[i];
		} else {
			sum1[i] = sum1[i - 1];
			sum2[i] = sum2[i - 1];
		}
	}
	int h = 0;
	for (int i = 1; i <= m; i++)
		h += (sum1[right[i]] - sum1[left[i] - 1]) * (sum2[right[i]] - sum2[left[i] - 1]);
	sum = abs(h - s);
	if (h > s)
		return 1;
	return 0;
}

main() {
	scanf("%lld%lld%lld", &n, &m, &s);
	for (int i = 1; i <= n; i++) {
		scanf("%lld %lld", &kun[i], &hun[i]);
		r = r > kun[i] ? r : kun[i];
		l = l < kun[i] ? l : kun[i];
	}
	for (int i = 1; i <= m; i++) {
		scanf("%lld%lld", &left[i], &right[i]);
	}
	l -= 1, r += 2;
	while (l <= r) {
		mid = (l + r) >> 1;
		if (check(mid)) { //检查该值是否小于上一值
			l = mid + 1;
		} else
			r = mid - 1 ;
		anser = anser < sum ? anser : sum;
	}
	anser = anser < sum ? anser : sum;
	printf("%lld", anser);
	return 0;
}