hdu 2779

贪心，注意贪的不是终止时间，因为有可能数据：

 

5
9 10
9 10
8 11
10 11
10 11

 

 

如果贪心贪终止时间结果是4，而事实上[8,9]是可以用的

 

#include<iostream> #include<algorithm> #include<functional> #include<queue> using namespace std; bool flag[50]; struct time { int start; int end; bool operator <(const time a)const { if(a.end==end) return a.start<start; return a.end<end; } }now,temp; int main() { priority_queue<time>Q; int i,n,j=0,t; while(++j) { memset(flag,false,sizeof(flag)); scanf("%d",&n); if(!n) return 0; for(i=0;i<n;i++) { scanf("%d%d",&now.start,&now.end); now.start*=2,now.end*=2; Q.push(now); } now.start=now.end=8*2; int count=0; while(!Q.empty()) { temp=Q.top(); Q.pop(); for(t=temp.start;t<=temp.end-1;t++) if(flag[t]==false) { now.start=max(t,now.start+1); flag[t]=true; count++; break; } } printf("On day %d Emma can attend as many as %d parties./n",j,count); } }