Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Maximizing Unique Pairs from two arrays in C++
Problem statement
Given two arrays of equal size N, form maximum number of pairs by using their elements, one from the first array and second from the second array, such that an element from each array is used at-most once and the absolute difference between the selected elements used for forming a pair is less than or equal to a given element K.
Example
If input is −
arr1[] = {3, 4, 5, 2, 1}
arr2[] = {6, 5, 4, 7, 15}
and k = 3 then we can form following 4 pairs whose absolute difference is less than or equal to 3 −
(1, 4), (2, 5), (3, 6), (4, 7)
Algorithm
We can use recursive approach to solve this problem
- Sort both the arrays
- Compare each element of the first array with each element of the second array for the possible pair, if it’s possible to form a pair
- Continue to check for the next possible pair for the next element of the first array.
Example
Let us now see an example −
#include <bits/stdc++.h>
using namespace std;
int getMaxUniquePairs(int *arr1, int *arr2, int n, int k) {
sort(arr1, arr1 + n);
sort(arr2, arr2 + n);
bool visited[n];
memset(visited, false, sizeof(visited));
int pairCnt = 0;
for (int i = 0; i < n; ++i) {
for (int j = 0; j < n; ++j) {
if (abs(arr1[i] - arr2[j]) <= k &&
visited[j] == false) {
++pairCnt;
visited[j] = true;
break;
}
}
}
return pairCnt;
}
int main() {
int arr1[] = {3, 4, 5, 2, 1};
int arr2[] = {6, 5, 4, 7, 15};
int n = sizeof(arr1) / sizeof(arr1[0]);
int k = 3;
cout << "Maximum unique pairs = " << getMaxUniquePairs(arr1, arr2, n, k) << endl;
return 0;
}Output
Maximum unique pairs = 4
Updated on: 31-Dec-2019
238 Views
Advertisements