題意:lrj白書上的一道題,給出一串數字,求第k個v出現時的下標;
思路:用STL裏的map和vector輕鬆的解決。。
#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;
}