HDU 6215 Brute Force Sorting

题目：http://acm.split.hdu.edu.cn/showproblem.php?pid=6215

题意：给定一个序列，每次删除序列中所有在下滑趋势中的点，问最后剩下的序列

 

设置一个队列，将可能产生下滑趋势的点放入

每次取出数时，如果被删除了，则将它前面一个点放入队列

#include<cstdio>
#include<iostream>
#include<cmath>
#include<queue>
#include<map>
#include<set>
#include<stack>
#include<stack>
#include<string>
#include<sstream>
#include<cstring>
#include<algorithm>
using namespace std;
const int N=1e5;
int nextt[N+5],last[N+5],a[N+5],que[N+5];
int main()
{
    int T;
    scanf("%d",&T);
    while(T--)
    {
        int n;
        scanf("%d",&n);
        int ans=n;
        a[0]=0;
        nextt[0]=1;
        last[n+1]=n;
        int top=0;
        for(int i=1;i<=n;i++)
        {
            scanf("%d",&a[i]);
            nextt[i]=i+1;
            last[i]=i-1;
            que[top++]=i;
        }
        int flag=1;
        while(flag)
        {
            flag=0;
            int s=0;
            int now=0;
            while(now<top)
            {
                int i=que[now],f=0;
                while(nextt[i]<=n)
                {
                    if (a[i]>a[nextt[i]])
                    {
                        f++;
                        i=nextt[i];
                        flag=1;
                    }
                    else break;
                }
                if (f)
                {
                    ans-=(f+1);
                    nextt[last[que[now]]]=nextt[i];
                    last[nextt[i]]=last[que[now]];
                    que[s++]=last[que[now]];
                }
                while(que[now]<=i&&now<top) now++;
            }
            top=s;
        }
        printf("%d\n",ans);
        int now=nextt[0];
        while(now<=n)
        {
            printf("%d ",a[now]);
            now=nextt[now];
        }
        printf("\n");
    }
    return 0;
}