HDU ACM 5249 KPI->ツリー配列+二分

#include<iostream>
#include<queue>
#include<algorithm>
using namespace std;

#define    N 10005
int c[N<<2];
int n,a[N],b[N];
char str[N][10];

int lowbit(int x)
{
    return x&(-x);
}

void update(int x,int val)
{
    while(x<N)
    {
        c[x]+=val;
        x+=lowbit(x);
    }
}

int sum(int x)
{
    int s=0;

    while(x>0)
    {
        s+=c[x];
        x-=lowbit(x);
    }
    return s;
}

int solve(int x)
{
    int id,l,r,mid;

    id=x/2+1;
    l=1;
    r=N;
    while(l<=r)
    {
        mid=(l+r)>>1;
        if(sum(mid)>=id)
            r=mid-1;
        else
            l=mid+1;
    }
    return b[l];
}

int main()      
{
    int x,T=0,i,cnt;

    while(scanf("%d",&n)==1)
    {
        queue<int> q;
        memset(c,0,sizeof(c));
        cnt=1;
        for(i=1;i<=n;i++)
        {
            scanf("%s",str[i]);
            if(str[i][0]=='i')
            {
                scanf("%d",&x);
                b[cnt++]=x;
                a[i]=x;
            }
        }
        sort(b+1,b+cnt+1);                   //  
        cnt=unique(b+1,b+cnt+1)-(b+1);         //  

        printf("Case #%d:
",++T);
        for(i=1;i<=n;i++)
        {
            if(str[i][0]=='i')
            {
                x=lower_bound(b+1,b+cnt+1,a[i])-b;
                update(x,1);
                q.push(x);           //         
            }
            else if(str[i][0]=='o')
            {
                x=lower_bound(b+1,b+cnt+1,b[q.front()])-b;
                update(x,-1);
                q.pop();
            }
            else if(str[i][0]=='q')
                printf("%d
",solve(q.size()));
        }
    }
    return 0;      
}