用堆来维护每个组的max_r
1 #include <bits/stdc++.h> 2 using namespace std; 3 const int N = 100010; 4 struct Range { 5 int l, r; 6 } range[N]; 7 bool cmp(Range r1, Range r2) { 8 return r1.l < r2.l; 9 } 10 int main() { 11 int n; 12 cin >> n; 13 for (int i = 0; i < n; i++) { 14 cin >> range[i].l >> range[i].r; 15 } 16 sort(range, range + n, cmp); 17 priority_queue<int, vector<int>, greater<int>> heap; 18 for (int i = 0; i < n; i++) { 19 Range t = range[i]; 20 if (!heap.size() || heap.top() >= t.l) { //需要开一个新的组 21 heap.push(t.r); 22 } else { //放进这个组里，更新max_r 23 heap.pop(); 24 heap.push(t.r); 25 } 26 } 27 cout << heap.size() << endl; 28 return 0; 29 }