离散化

离散化

#include <bits/stdc++.h>
using namespace std;
#define LL long long
const int N = 3e5 + 10;
LL n, m, a[N], s[N];
int main(){
	ios::sync_with_stdio(false);cin.tie(0);
	cin >> n >> m;
	vector <LL> num;
	vector <pair <LL, LL>> add, q;
	for (int i = 0; i < n; i ++ ){
		LL x, c;
		cin >> x >> c;
		num.push_back(x);
		add.push_back({x, c});
	}
	for (int i = 0; i < m; i ++ ){
		LL l, r;
		cin >> l >> r;
		q.push_back({l, r});
		num.push_back(l);
		num.push_back(r);
	}
	sort(num.begin(), num.end());
	num.erase(unique(num.begin(), num.end()), num.end());
	for (auto x : add){
		LL t = lower_bound(num.begin(), num.end(), x.first) - num.begin() + 1;
		a[t] += x.second;
	}
	for (int i = 1; i <= (int)num.size(); i ++ )
		s[i] = s[i - 1] + a[i];
	for (auto x : q){
		LL l = lower_bound(num.begin(), num.end(), x.first) - num.begin() + 1;
		LL r = lower_bound(num.begin(), num.end(), x.second) - num.begin() + 1;
		cout << s[r] - s[l - 1] << "\n";
	}
	return 0;
}

自定义 unique 函数

vector <int> :: iterator unique(vector <int> &a){
	int j = 0;
	for (int i = 0; i < a.size(); i++)
		if (!i || a[i] != a[i - 1])
			a[j++] = a[i];
	return a.begin() + j;
}

acwing: https://www.acwing.com/problem/content/804/