1、将所有区间按照左端点从小到大排序
2、从前往后处理每个区间
判断能否将其放到某个现有的组中 L[i] > Max_r
(1)如果不存在这样的组,则开新组,然后将其放进去;
(2)如果存在这样的组,将其放进去,并更新当前组的Max_r
#include <iostream>
#include <algorithm>
#include <queue>
using namespace std;
const int N = 100010;
int n;
struct Range
{
int l, r;
bool operator < (const Range &w) const
{
return l < w.l;
}
}range[N];
int main()
{
scanf("%d", &n);
for (int i = 0; i < n; ++ i)
{
scanf("%d %d", &range[i].l, &range[i].r);
}
sort(range, range + n);
priority_queue<int, vector<int>, greater<int>> heap;
for (int i = 0; i < n; ++ i)
{
if (heap.empty() || heap.top() >= range[i].l) heap.push(range[i].r);
else
{
heap.pop();
heap.push(range[i].r);
}
}
printf("%d\n", heap.size());
return 0;
}