uva 11991 - Easy Problem from Rujia Liu?

#include<vector>
#include<cstdio>
#include<map>
#define maxn 1000009
using namespace std;

vector<int>ve[maxn];
map<int,vector<int> >mp;
int n,m,x,y;
int main()
{
while(scanf("%d%d",&n,&m)!=EOF)
{
mp.clear();
for(int i=0;i<n;i++)
{
scanf("%d",&x);
if(!mp.count(x))mp[x]=vector<int>();
mp[x].push_back(i+1);
}
while(m--)
{
scanf("%d%d",&x,&y);
if(!mp.count(y)||mp[y].size()<x)puts("0");
else printf("%d\n",mp[y][x-1]);
}
}
return 0;
}