NOIP2017普及组——图书管理员

#include<bits/stdc++.h>
#define MAX_N 1000+10
using namespace std;
int isb[MAX_N];
int n,q;

inline int read()
{
    int 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<<1)+(x<<3)+(ch^48),ch=getchar();
    return x*f;
}

int calc(int bm,int len)
{
    int e=0;
    while(bm){e=(e<<1)+(e<<3)+bm%10;bm/=10;}
    for(int i=1;i<=n;i++)
    {
        int now=isb[i],cm=0;
        for(int j=1;j<=len;j++){cm=(cm<<1)+(cm<<3)+now%10;now/=10;}
        if(cm==e)
            return isb[i];
    }
    return -1;
}

int main()
{
    freopen("librarian.in","r",stdin);
    freoepn("librarian.out","w",stdout);
    n=read();q=read();
    for(int i=1;i<=n;i++)isb[i]=read();
    sort(isb+1,isb+n+1);
    for(int i=1;i<=q;i++)
    {
        int l=read(),need=read();
        int ans=calc(need,l);
        printf("%d\n",ans);
    }
    return 0;
}