题目链接：区间和

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

using namespace std;

typedef pair<int, int> PII;

const int N = 300010;

int n, m;
int a[N], s[N];
vector<int> alls;
vector<PII> add, query;

// 求x离散化之后的结果
int find(int x)
{
    int l = 0, r = alls.size() - 1;
    while(l < r)
    {
        int mid = l + r >> 1;
        if(alls[mid] >= x) r = mid;
        else l = mid + 1;
    }
    return r + 1;
}

int main()
{
    cin >> n >> m;
    for(int i = 0; i < n; i++)
    {
        int x, c;
        cin >> x >> c;
        add.push_back({x, c});
        alls.push_back(x);
    }
    
    for(int i = 0; i < m; i++)
    {
        int l, r;
        cin >> l >> r;
        query.push_back({l, r});
        alls.push_back(l);
        alls.push_back(r);
    }
    // 去重
    sort(alls.begin(), alls.end());
    alls.erase(unique(alls.begin(), alls.end()), alls.end());
    
    // 处理插入
    for(auto item: add)
    {
        int x = find(item.first);
        a[x] += item.second;
    }
    // 预处理前缀和
    for(int i = 1; i <= alls.size(); i ++) s[i] = s[i - 1] + a[i];
    // 处理询问
    for(auto item: query)
    {
        int l = find(item.first), r = find(item.second);
        cout << s[r] - s[l - 1] << endl;
    }
    return 0;
}