BZOJ1046 上升序列

#include<bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp make_pair
#define se second
#define fs first
#define ll long long
#define CLR(x) memset(x,0,sizeof x)
#define MC(x,y) memcpy(x,y,sizeof(x))  
#define SZ(x) ((int)(x).size())
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin();it!=(c).end();it++)
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1 
#define INF 2097152
typedef pair<int,int> P;
const double eps=1e-9;
const int maxn=10010;
const int mod=10007;
    
ll read()
{
    ll x=0,f=1;char ch=getchar();
    while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
    while(ch>=‘0‘&&ch<=‘9‘){x=x*10+ch-‘0‘;ch=getchar();}
    return x*f;
}
//-----------------------------------------------------------------------------
    
int a[maxn],b[maxn],c[maxn],f[maxn];

int bs(int m,int l,int r)//大于m的最小数 
{
    int L,R,Mid,Goal;
    L=1,R=r+1;
    while(L<=R)
    {
        Mid=(L+R)>>1;
        if(c[Mid]>m)
        {
            Goal=Mid;
            L=Mid+1;
        }
        else R=Mid-1;
    }
    return Goal;
}

int main()
{
    int n,m,p;
    n=read();
    for(int i=1;i<=n;i++)
    {
        a[i]=read();
        b[n+1-i]=a[i];
    }
    int tmp=1;
    c[tmp]=b[1];
    f[n]=1;
    for(int i=2;i<=n;i++)
    {
        if(b[i]<c[tmp])
        {
             c[++tmp]=b[i];
             f[n+1-i]=tmp;
        }
        else
        {
            int pos=bs(b[i],1,tmp);
            f[n+1-i]=pos+1;
            if(c[pos+1]<b[i]) c[pos+1]=b[i];
        }
    }
    m=read();
    a[0]=-INF;
    int pos;
    for(int i=1;i<=m;i++)
    {
        p=read();
        if(p>tmp) printf("Impossible\n");
        else
        {
            pos=0;
            for(int i=1;i<=n;i++)
            {
                if(!p) break;
                if(f[i]>=p&&a[i]>a[pos])
                {
                    if(p>1) printf("%d ",a[i]);
                    else    printf("%d\n",a[i]);
                    p--;
                    pos=i;
                }
            }
        }
    }
    return 0;
}