BZOJ1029: [JSOI2007]建筑抢修(贪心)

Posted 2020-08-08

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。

 1 #include<stdio.h>
 2 #include<queue>
 3 #include<algorithm>
 4 using namespace std;
 5 const int N = 150001;
 6 struct node{
 7     int t1, t2;
 8 }s[N];
 9 
10 int cmp(node a, node b){
11     return a.t2 < b.t2;
12 }
13 
14 int main(){
15     int n, t1, t2, i, cur;
16     scanf("%d", &n);
17     for(i = 0; i < n; ++i)
18         scanf("%d %d", &s[i].t1, &s[i].t2);
19     sort(s, s+n, cmp);
20     priority_queue<int>q;
21     for(cur = i = 0; i < n; ++i){
22         if(cur + s[i].t1 < s[i].t2){
23             q.push(s[i].t1);
24             cur += s[i].t1;
25         }
26         else if(!q.empty()&& s[i].t1 < q.top()){
27             cur = cur -q.top() + s[i].t1;
28             q.pop();
29             q.push(s[i].t1);
30         }
31     }
32     printf("%d\n", q.size());
33     return 0;
34 }

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