UVA - 11991 - Easy Problem from Rujia Liu? （STL）

RujiaLiu的简易问题求解

最新推荐文章于 2021-01-30 23:15:56 发布

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本文介绍了一个由RujiaLiu提出的算法挑战，任务是在给定数组中找出特定整数的第k次出现的位置。通过使用C++实现的高效算法解决这一问题，并提供了完整的代码示例。

Easy Problem from Rujia Liu?

Time Limit: 1000MS

Memory Limit: Unknown

64bit IO Format: %lld & %llu

Submit Status

Description

Problem E

Easy Problem from Rujia Liu?

Though Rujia Liu usually sets hard problems for contests (for example, regional contests like Xi'an 2006, Beijing 2007 and Wuhan 2009, or UVa OJ contests like Rujia Liu's Presents 1 and 2), he occasionally sets easy problem (for example, 'the Coco-Cola Store' in UVa OJ), to encourage more people to solve his problems :D

Given an array, your task is to find the k-th occurrence (from left to right) of an integer v. To make the problem more difficult (and interesting!), you'll have to answer m such queries.

Input

There are several test cases. The first line of each test case contains two integers n, m(1<=n,m<=100,000), the number of elements in the array, and the number of queries. The next line contains n positive integers not larger than 1,000,000. Each of the following m lines contains two integer k and v (1<=k<=n, 1<=v<=1,000,000). The input is terminated by end-of-file (EOF). The size of input file does not exceed 5MB.

Output

For each query, print the 1-based location of the occurrence. If there is no such element, output 0 instead.

Sample Input

8 4
1 3 2 2 4 3 2 1
1 3
2 4
3 2
4 2

Output for the Sample Input

#include<cstdio>
#include<algorithm>
#include<vector>
using namespace std;
const int N = 1000000 + 10;
vector<int> a[N];
int n, m;
int main(){
	while(scanf("%d%d", &n, &m) != EOF){
		for(int i = 1; i <= n; i++) a[i].clear();
		for(int i = 1; i <= n; i++){
			int b;
			scanf("%d", &b);
			a[b].push_back(i);
		}
		while(m--){
			int k,v;
			scanf("%d%d", &k, &v);
			if(k > a[v].size() || a[v].size() == 0) printf("0\n");
			else printf("%d\n", a[v][k - 1]);
		}
	}
	return 0;
}