UVA 11991

题意：lrj白书上的一道题，给出一串数字，求第k个v出现时的下标；

思路：用STL里的map和vector轻松的解决。。

#include <set>
#include <map>
#include <cmath>
#include <stack>
#include <queue>
#include <string>
#include <vector>
#include <cstdio>
#include <climits>
#include <cstring>
#include <iostream>
#include <algorithm>
#define LL long long
#define pub push_back
#define inst insert
#define mp make_pair
#define SZ(x) ((int)(x).size())
#define ForEach(i,c) for(__typeof((c).begin()) i = (c).begin();i != (c).end();i++)
using namespace std;


int main(){
	int n, q;
	while(cin >> n >> q){
		map<int, vector<int> > M;
		int i, num, k, v;
		for(i = 1;i <= n;i++){
			cin >> num;
			if(SZ(M[num]) == 0)
				M[num] = vector<int>();
			M[num].push_back(i);
		}
		while(q--){
			scanf("%d%d", &k, &v);
			if(SZ(M[v]) < k)
				printf("0\n");
			else 
				printf("%d\n", *(M[v].begin() + k - 1));
		}
			
	}
	return 0;
}