一層一層刪

鏈表模擬

#include <iostream>
#include <cstring>
#include <algorithm>
#include <cstdio>
using namespace std;
const int maxn = 1e5 + 7;
int que[maxn], a[maxn], pre[maxn], suf[maxn], n, top;
int main()
{
    int _;
    cin >> _;
    while(_--)
    {
        top = 0;
        scanf(
 
"%d", &n);
        for(int i = 1; i <= n; i++)
        {
            pre[i] = i-1;
            suf[i] = i+1;
            scanf("%d", &a[i]);
            que[top++] = i;
        }
        suf[0] = 1;
        int ans = n, flag = 0;
        while(1)  //一輪一輪的刪， 如果沒有改動過，說明都是有序的了
        {
            
 
int cnt = 0, cur = 0, flag = 0;
            while(cur < top)  //當前這一輪
            {
                int p = que[cur], num = 0;
                while(suf[p] <= n && a[p] > a[suf[p]])  //把一個連續的刪掉
                {
                    flag = 1;
                    num++;
                    p 
 
= suf[p];
                }
                if(num)
                {
                    ans -= num+1;
                    suf[pre[que[cur]]] = suf[p];  //維護鏈表，使其聯通
                    pre[suf[p]] = pre[que[cur]];
                    que[cnt++] = pre[que[cur]];
                }
                while(que[cur] <= p && cur < top)  //修改當前指針
                    cur++;
            }
            top = cnt;
            if(!flag) break;  //沒有就跳出
        }
        printf("%d\n", ans);
        int cur = 0;
        while(cur <= n)
        {
            if(cur)
                printf("%d ",a[cur]);
            cur = suf[cur];
        }
        puts("");
    }
    return 0;
}

HDU 6215 Brute Force Sorting