[Ural1306] Sequence Median（網上很多題解騙人，這才是對的！業界良心！）

標籤：

血的教訓：

1. 盡信題解，不如無題解！

2. C++ STL很坑爹。。

測試結果分析與比較：

#1是我自己寫的，使用priority_queue，超記憶體：

#include <cstdio>#include <cstring>#include <algorithm>#include <queue>using namespace std;priority_queue <unsigned int> pq;int main(){    unsigned int n,i,x,s1,s2;    scanf("%d",&n);    if(n % 2 != 0){        for(i=1;i<=n;i++){            scanf("%d",&x);            pq.push(x);            if(pq.size() == n/2+2){                pq.pop();            }        }        printf("%.1lf\n",(double)pq.top());    }    else{        for(i=1;i<=n;i++){            scanf("%d",&x);            pq.push(x);            if(pq.size() == n/2+2){                pq.pop();            }        }        s1 = pq.top();        pq.pop();        s2 = pq.top();        printf("%.1lf\n",(double)(s1+s2)/2);    }    return 0;}

#2 from PegasusWang http://www.cnblogs.com/PegasusWang/archive/2013/03/23/2977597.html

使用priority_queue,同樣超記憶體

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <queue> //for priority_queue
using namespace std;
int main()
{
priority_queue<unsigned int> ipq;
int n;
scanf("%d", &n);
unsigned int t;
for (int i = 1; i <= n / 2 + 1; ++i)
{
scanf("%u", &t);
ipq.push(t);
}
int tn = n / 2 + 2;
while (tn <= n)
{
scanf("%u", &t);
ipq.push(t);
++tn;
ipq.pop();
}
if (n & 1) //if n is odd
printf("%u.0\n", ipq.top());
else
{
int t1 = ipq.top();
ipq.pop();
printf("%.1f", (double)(t1 + ipq.top()) / 2);
}
return 0;
}

#3 from 不許偷懶啦小鬼 http://blog.csdn.net/yujuan_mao/article/details/7985424

使用priorty_queue，還是超記憶體

#include<cstdio>#include<iostream>#include<queue>#include<vector>#include<algorithm>using namespace std;int main(){    unsigned int n,temp,i,j,k,m,x,y;    priority_queue<unsigned int,vector<unsigned int>,greater<unsigned int> > Q;    cin>>n;    for(i=0;i<n;i++){        scanf("%u",&m);        Q.push(m);        if(Q.size()>(n/2+1))            Q.pop();    }    if(n%2)        printf("%.1lf\n",1.0*Q.top());    else{        x=Q.top();        Q.pop();        y=Q.top();        printf("%.1lf\n",1.0*(x+y)/2);    }    return 0;}

#4 from http://www.zgxue.com/163/1639818.html

使用數組和堆，AC

#include <iostream>#include <algorithm>#include <cstdio>#include <cstring>#include <vector>#include <queue>using namespace std;const int maxn=250000;int a[maxn/2+10];int main(){    int n;double ans;    while(scanf("%d",&n)!=EOF)    {       int num=0,x;       for(int i=0;i<n/2+1;i++)       scanf("%d",&a[i]);       make_heap(a,a+n/2+1);       for(int i=n/2+1;i<n;i++)       {           scanf("%d",&x);           if(x<a[0])           {               pop_heap(a,a+n/2+1);               a[n/2]=x;               push_heap(a,a+n/2+1);           }       }       if(n%2)       {           ans=(double)a[0];           printf("%.1lf\n",ans);       }       else       {           ans=(double)a[0];           pop_heap(a,a+n/2+1);           ans+=(double)a[0];           printf("%.1lf\n",ans/2.0);       }    }    return 0;}

 

The standard container adaptor priority_queue calls make_heap, push_heap and pop_heap automatically to maintain heap properties for a container.

 

[Ural1306] Sequence Median（網上很多題解騙人，這才是對的！業界良心！）