BZOJ1029: [JSOI2007]建筑抢修(贪心)

题目链接：BZOJ1029: [JSOI2007]建筑抢修

题解：贪心思想，按结束时间从小到大排序，选花费时间尽量短的建筑维修，用堆维护。

#include<stdio.h>
#include<queue>
#include<algorithm>
using namespace std;
const int N = 150001;
struct node{
    int t1, t2;
}s[N];

int cmp(node a, node b){
    return a.t2 < b.t2;
}

int main(){
    int n, t1, t2, i, cur;
    scanf("%d", &n);
    for(i = 0; i < n; ++i)
        scanf("%d %d", &s[i].t1, &s[i].t2);
    sort(s, s+n, cmp);
    priority_queue<int>q;
    for(cur = i = 0; i < n; ++i){
        if(cur + s[i].t1 < s[i].t2){
            q.push(s[i].t1);
            cur += s[i].t1;
        }
        else if(!q.empty()&& s[i].t1 < q.top()){
            cur = cur -q.top() + s[i].t1;
            q.pop();
            q.push(s[i].t1);
        }
    }
    printf("%d\n", q.size());
    return 0;
}