宁波工程学院 OJ [1282] A Bouquet of Flowers 最大的k个数的和

• 问题描述
• Mr.Cai want to send TT a bouquet of the most beautiful flowers.
  Mr.Cai have buy K bouquets of flowers from the shop.
  When Mr.Cai get the bouquet of flowers that will sorted in descending order by their beautiful value.
  And Mr.Cai want pick up H flowers from the K bouquets to make up the most beautiful bouquet flowers.
• 输入
• There are muti-case.
  First line contain two integers K (0 < K <= 1000) and H (0 < H <= 1000)
  Then there are K lines.
  For each lines, the first number Ni (0 < Ni <= 10000) means the bouquet of flowers contains Ni flowers.
  the following Ni numbers means the flower's beautiful value Vi (0 < Vi <= 100000).
  The H is less than the sum of all Ni.
  
• 输出
• For each case, print the most beautiful flowers's beatiful value.
  
• 样例输入

• 2 33 3 2 13 6 5 42 43 4 2 13 3 2 1

• 样例输出

• 1511

• 提示

• 无

• 来源

• Monkeyde17

题意：输入  h  k
表示h行  每行   第一个数m  其后跟m个数字 

问这些数字中取k个  问和最大为多少？

思路：

由于   只有444k的内存 所以要用到 优先队列      保持k个数

但是 我的却一直超时   看了别人的解题报告才知道  语句中多很多判断 比入队出队要耗的时间少很多     也就是 本题的主要耗时间的地方时入队出队

下面是AC 代码 最后面是TLE的

AC

#include<stdio.h>#include<stdlib.h>#include<queue>using namespace std;int main(){int h,i,j,n,k;while(scanf("%d %d",&k,&h)!=EOF){priority_queue<int,vector<int>,greater<int> >que;while(k--){scanf("%d",&n);int num;while(n--){scanf("%d",&num);if(que.size()<h)que.push(num);else if(que.size()>=h&&num>que.top()) {que.pop();que.push(num);}}}int sum=0;while(que.size()>h) que.pop();while(!que.empty()){sum+=que.top();que.pop();}printf("%d\n",sum);}return 0;}

TLE

#include<stdio.h>#include<stdlib.h>#include<queue>using namespace std;int main(){int h,i,j,n,k;while(scanf("%d %d",&k,&h)!=EOF){priority_queue<int,vector<int>,greater<int> >que;while(!que.empty()){que.pop();}while(k--){scanf("%d",&n);int num;while(n--){scanf("%d",&num);que.push(num);if(que.size()>h) que.pop();}}int sum=0;while(que.size()>h) que.pop();while(!que.empty()){sum+=que.top();que.pop();}printf("%d\n",sum);}return 0;}

上面的 AC的982ms 

下面处理了下  就200ms

#include<stdio.h>#include<stdlib.h>#include<queue>using namespace std;int getval(){         int ret(0);         char c;         while((c=getchar())==' '||c=='\n'||c=='\r');             ret=c-'0';         while((c=getchar())!=' '&&c!='\n'&&c!='\r')                             ret=ret*10+c-'0';             return ret;}int main(){int h,i,j,n,k;while(scanf("%d %d",&k,&h)!=EOF){priority_queue<int,vector<int>,greater<int> >que;while(k--){scanf("%d",&n);int num;while(n--){num=getval();if(que.size()<h)que.push(num);else if(que.size()>=h&&num>que.top()) {que.pop();que.push(num);}}}int sum=0;while(que.size()>h) que.pop();while(!que.empty()){sum+=que.top();que.pop();}printf("%d\n",sum);}return 0;}