题目描述

模板题：离散化

C++代码

#include <bits/stdc++.h>
using namespace std;

typedef pair<int, int> PII;
const int N = 3e5 + 10;
int n, m, l, r, c, x;
int a[N], s[N];
vector<int> alls;
vector<PII> adds;
vector<PII> querys;

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 l + 1;
}

int main(){
    cin >> n >> m;
    for(int i = 0; i < n; i++){
        cin >> x >> c;
        alls.push_back(x);
        adds.push_back({x, c});
    }
    for(int i = 0; i < m; i++){
        cin >> l >> r;
        alls.push_back(l);
        alls.push_back(r);
        querys.push_back({l, r});
    }
    sort(alls.begin(), alls.end());
    alls.erase(unique(alls.begin(), alls.end()), alls.end());
    for(auto item : adds){
        int index = find(item.first);
        a[index] += item.second;
    }
    for(int i = 1; i <= alls.size(); i++)
        s[i] += s[i - 1] + a[i];
    for(auto item : querys){
        l = find(item.first);
        r = find(item.second);
        cout << s[r] - s[l - 1] << endl;
    }
}