C - Functions again CodeForces - 789C

C - Functions again

 CodeForces - 789C 

这道题考查了对Map的运用 

#include<iostream>
#include<cstdio>
#include<map>
#include<cmath>
using namespace std;
typedef long long ll;
map<ll,ll> maps;
ll b1,q,l,m,ans;
int main()
{
    cin>>b1>>q>>l>>m;
    for(int i=0;i<m;++i)
    {
        ll p;
        scanf("%lld",&p);
        maps[p]=1;
    }
    if(b1==0)
    {
        if(maps[0]==0) printf("inf"); 
        else printf("0");
        return 0;
    }
    else if(q==0)
    {
        if(abs(b1)>l) 
        printf("0");
        else if(maps[0]==0) printf("inf");
        else if(maps[b1]==0) printf("1");
        else printf("0");
        return 0;    
    }
    else if(q==1) 
    {
        if(abs(b1)<=l&&maps[b1]==0) 
        printf("inf");
        else
         printf("0");
        return 0;
    }
    else if(q==-1)
    {
        if(abs(b1)>l) printf("0");
        else if(!maps[b1]||!maps[-b1]) printf("inf");
        else printf("0");
        return 0;
    }
    ll e=b1;
    while(abs(e)<=l)
    {
        if(maps[e]==0) ++ans;
        e*=q;
    }
    printf("%lld",ans);
    return 0;
}