题目描述

模板题：区间合并

C++代码

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

typedef pair<int, int> PII;
const int N = 1e5 + 10;
int n, l, r;
vector<PII> alls;

void merge(vector<PII> &segs){
    vector<PII> res;
    int st = -1e9, ed = -1e9;
    sort(segs.begin(), segs.end());
    for(auto item : segs){
        if(ed < item.first){
            if(st != -1e9)
                res.push_back({st, ed});
            st = item.first;
            ed = item.second;
        }
        else
            ed = max(ed, item.second);
    }
    if(st != -1e9)
        res.push_back({st, ed});
    segs = res;
}

int main(){
    cin >> n;
    for(int i = 0; i < n; i++){
        cin >> l >> r;
        alls.push_back({l, r});
    }
    merge(alls);
    cout << alls.size() << endl;
}