(DS "algorithm Primer classic") UVA 11991 Easy problem from Rujia Liu? (Index of K-V occurrences)

Main topic:

Index of K-V occurrences

Problem Solving Ideas:

If a data structure can be constructed, so that data[v][k] is the index value of K-V can be solved. DATA[V] represents an array of indices that appear as a number V,

DATA[V][K] represents the index of the first K v occurrence.

Problem eeasy problem from Rujia Liu?

Though Rujia Liu usually sets hard problems for contests (for example, regional contests like Xi ' an 2006, Beijing Wuhan, or UVa OJ contests like Rujia Liu's presents 1 and 2), he occasionally sets easy problem (for example, ' the C Oco-cola Store ' in UVa OJ-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. The problem more difficult (and interesting!), you'll have to answer m such queries.

Input

There is several test cases. The first line of all test case contains-integers n, m (1<=n,m<=100,000), the number of elements in the array, a nd the number of queries. The next line contains n positive integers not larger than 1,000,000. Each of the following m lines contains the 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 41 3 2 2 4 3 2 11 32 43 24 2

Output for the Sample Input

2070

Rujia Liu ' s Present 3: A Data Structure Contest celebrating the 100th anniversary of Tsinghua University
Special thanks:yiming Li
Note:please Make sure to test your program with the gift I/O files before submitting!

The code is as follows:

/* * uva_11991.cpp * *  Created on:2014 December 28 *      author:administrator * * #include <iostream> #include <cs tdio> #include <map> #include <vector>using namespace Std;map<int,vector<int> > Mp;int n,m; int main () {while (scanf ("%d%d", &n,&m)!=eof) {mp.clear (); int i;for (i = 0; i < n; ++i) {int tmp;scanf ("%d", &t MP);/** * Returns the number of occurrences of the key k in the map (for map, because a key corresponds to a value, * Therefore returns only 0 and 1, so you can use this function to determine whether K is in the map) */if (mp.count (tmp) = = 0) {// If this key value does not appear over mp[tmp] = vector<int> ();//Then create a new vector. Notice here that the instantiation of the vector ()}mp[tmp].push_back (i+1);} while (m--) {int k,v;scanf ("%d%d", &k,&v), if (Mp.count (v) = = 0 | | mp[v].size () < K) {//If this value does not exist, or the location that needs to be accessed exceeds the number of occurrences of this only occurrence of printf ("0\n");//Print 1}else{printf ("%d\n", Mp[v][k-1]);}} return 0;}

(DS "algorithm Primer classic") UVA 11991 Easy problem from Rujia Liu? (Index of K-V occurrences)