uva11991 Easy Problem from Rujia Liu?（STL）

思路：给你一串数字，每次询问k,v，输出代表第K个V的下标，直接用STL搞搞

#include<iostream>
#include<map>
#include<vector>
#include<cstdio>
using namespace std;

int main()
{
     int n,q;
	 while(scanf("%d%d",&n,&q)!=EOF)
	 {
		 map<int,vector<int> >mp;
		 for(int i = 1;i<=n;i++)
		 {
			  int x;
              scanf("%d",&x);
			  if(!mp.count(x))
			  {
				  mp[x] = vector<int>();
				  mp[x].push_back(i);
			  }
			  else
				  mp[x].push_back(i);
		 }
		 while(q--)
		 {
              int v,k;
			  scanf("%d%d",&k,&v);
			  if(!mp.count(v))
			  {
				  printf("0\n");
				  continue;
			  }
			  else
			  {
				  if (mp[v].size()<k)
				  {
					  printf("0\n");
					  continue;
				  }
				  else
				  {
					  printf("%d\n",mp[v][k-1]);
				  }
			  }
		 }
	 }
}