Almost Sorted Array---hdu5532（j简单dp）

#include<stdio.h>
#include<string.h>
#include<algorithm>
#include<iostream>
#include<vector>
#include<queue>
#include<set>
using namespace std;
#define met(a, b) memset(a, b, sizeof(a))
#define N 100005
#define INF 0x3f3f3f3f
typedef long long LL;

int n, a[N], dp[N];

int solve1()
{
    for(int i=0; i<=n; i++)
        dp[i] = INF;
    int ans = 0;
    for(int i=1; i<=n; i++)
    {
        int pos = upper_bound(dp, dp+n, a[i]) - dp;
        dp[pos] = min(dp[pos], a[i]);
        ans = max(ans, pos);
    }
    return ans+1;
}
int solve2()
{
    for(int i=0; i<=n; i++)
        dp[i] = INF;
    int ans = 0;
    for(int i=n; i>=1; i--)
    {
        int pos = upper_bound(dp, dp+n, a[i]) - dp;
        dp[pos] = min(dp[pos], a[i]);
        ans = max(ans, pos);
    }
    return ans+1;
}

int main()
{
    int T;
    scanf("%d", &T);
    while(T--)
    {
        scanf("%d", &n);
        for(int i=1; i<=n; i++)
            scanf("%d", &a[i]);
        int ans1 = solve1();
        int ans2 = solve2();
        if(ans1 >= n-1 || ans2 >= n-1)
            puts("YES");
        else
            puts("NO");
    }
    return 0;
}