• 排序 + 前缀和
• 条条大路通罗马

#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>

using namespace std;

const int N = 1e5 + 10;

struct item
{
    int idx, val;
    bool operator < (const item &W) const
    {
        return idx < W.idx;
    }
}item[N];

int a[N];
int n, m;
int main()
{
    scanf("%d%d", &n, &m);
    int x, c;
    for (int i = 1; i <= n; i++)
    {
        scanf("%d%d", &item[i].idx, &item[i].val);
    }

    sort(item + 1, item + 1 + n);
    for (int i = 1; i <= n; i++)
    {
        item[i].val += item[i - 1].val; 
        a[i] = item[i].idx;
    }

    int l, r;
    while (m --)
    {
        scanf("%d%d", &l, &r);
        l = lower_bound(a + 1, a + 1 + n, l) - (a + 1) + 1;
        r = upper_bound(a + 1, a + 1 + n, r) - (a + 1) + 1;
        r--;
        int res = item[r].val - item[l - 1].val;
        printf("%d\n", res);
    }

    return 0;

}