HDU6058 (76/600)

Problem Description
Give you an array A[1..n]of length n.

Let f(l,r,k) be the k-th largest element of A[l..r].

Specially , f(l,r,k)=0 if r−l+1

#include<bits/stdc++.h>
using namespace std;
#define int unsigned long long 
#define ll unsigned long long 
int T,n,k,u=0,tu[501001],qian[501001],hou[501001],q,qq[101],ww[101];
void shanchu(int x)
{
    qian[hou[x]]=qian[x];
    hou[qian[x]]=hou[x];
}
int jiejue(int x)
{
    memset(qq,0,sizeof(qq));
    memset(ww,0,sizeof(ww));
    int er=0,re=0;
    for(int a=x;a<=n;a=hou[a])
    {
        qq[++re]=hou[a]-a;
        if(re==k)break;
    }
    for(int a=x;a;a=qian[a])
    {
        ww[++er]=a-qian[a];
        if(er==k)break;
    }
    int fs=0;
    for(int a=1;a<=er;a++)
    {
        if(k-a+1>re)continue;
        fs+=ww[a]*qq[k-a+1]*1ll;
    }
    return fs;
}
main()
{
//  freopen("1003in.txt", "r", stdin);
//  freopen("s.txt", "w", stdout);
    cin>>T;
    while(T--)
    {
        memset(tu,0,sizeof(tu));
        memset(qian,0,sizeof(qian));
        memset(hou,0,sizeof(hou));
        cin>>n>>k;
        for(int a=1;a<=n;a++)
        {
            scanf("%llu",&q);
            tu[q]=a;
            qian[a]=a-1;
            hou[a]=a+1;
        }
        qian[0]=0;
        hou[n+1]=n+1;
        hou[0]=1;
        qian[n+1]=n;
        int dan=0;
        for(int a=1;a<=n;a++)
        {
            dan+=a*jiejue(tu[a])*1ll;
            shanchu(tu[a]);
        }
        printf("%llu\n",dan);
    }
}