Find Pairs in Array with Given Sum | Programming Tutorials

In this tutorial, I have explained how to find pairs in array with given sum. Write a Java Program to find pairs with given sum in a sorted array.
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[@kingnani1557]

Super explanation brother... thanks

[@ProgrammingTutorials1M]

Thank you very much

[@kingnani1557]

@@ProgrammingTutorials1M 😁😁😁😁😁😁

[@hackernight5110]

for (int i = 0; i < arr.length; i++) {
for (int j = 0; j < arr.length; j++) {
if (arr[i]+arr[j]==sum)
System.out.println("Pair "+arr[i]+" , "+arr[j]);
}
}
With O(n^2) time complexity

[@charankumarreddy9495]

brooo thank u!! :')

[@tusharprajapati2574]

pairs repeat hoga

[@syedalluddin3977]

This will give duplicate pairs like for given sum 4 pairs will be -> 1+3 and 3+1 , I got rejected in the interview because I wrote the code in this approach , interviewer just said thanks and left the meeting

[@WeREmotional]

I had an interview earlier this week they asked me solve it without using loops but only using streams api.can you pleasehelp me.

[@garimanagarwal1571]

this one is for sorted array
please upload for unsorted array also

[@ProgrammingTutorials1M]

Code link is present in the description box.

[@xristosmestviridis3708]

great job man. Congratulations

[@ProgrammingTutorials1M]

Thank you very much.

[@susongbrit]

Sir i subscribed ur channel and i will share it to my other frnds also ..awesome explantaion thank you sir

[@ProgrammingTutorials1M]

Thank you so much.

[@chandanagoshika2454]

Super explanation..

[@rohitkushwaha6125]

Nice explanation. Sir sometimes it happens they ask to return array of such pairs how it could be done.

[@pritamagarwala9415]

time complexity will be O(log n)...right ?

[@TheEngineerFarm]

//for unsorted Arrays
// k mean sum and n length of arr
HashMapmap=new HashMap();
for(int i=0;i

[@abduchadili5691]

What if you have repeating pairs how would you code it ?

[@sdetbyraviteja568]

For that again we have to create one hash set and by using if condition by putting distinct pairs we can person the sum operation.

[@sarah-fu6hw]

thank you soo much your videos are soo helpful

[@ProgrammingTutorials1M]

You're so welcome!

[@togashiyuuta-s1p]

What if I want to find 6 variables not just 2 for the sum?

[@ndmotivations]

thanks a lot for geat explanation Sir.

[@ProgrammingTutorials1M]

You are most welcome

[@rohitshirodkar1129]

what if array has duplicate elements? then low++, high-- (on sum =9) wont work?

[@merxxibeaucoup9093]

I solved it using a hashset

[@simon-yi6jv]

@@merxxibeaucoup9093 only if array in sorted it will work

[@Hemavani-lx6zb]

awesome explanation, need program for : Write a java program for getting the sum of 30 by adding min 3 numbers from count[]={1, 15, 10, 5}. pleas help

[@abduchadili5691]

you don't need if equal test, just use else which is the only case left

[@lokeshborole8997]

for Unsorted ?

[@pradyumna668]

what if duplicate are present or array with same elements like {2,2,2,2} and the required sum is 4

[@ProgrammingTutorials1M]

For this problem, The array elements are distinct and in a sorted order

[@vipulraj_1193]

what if there are multiple numbers like example array 122344 and we have sum equal to 5 then how to do in this way

[@ProgrammingTutorials1M]

Are you talking about duplicates in an array and in that case we have to find the pair?

[@sankarpatra2788]

Sir please do some questions related to list stack and que

[@pratuu_s]

This program asked on technical round.

[@ashwinishete511]

Very nice ...plz make seris of interview prog...in this way

[@ProgrammingTutorials1M]

Thank you

[@siddhigolatkar8558]

Thank you

[@ProgrammingTutorials1M]

Thank you

[@amrish2181]

does it only work with sorted array?

[@ProgrammingTutorials1M]

Yes

[@adhvikworld1743]

In case of unsorted array?

[@ProgrammingTutorials1M]

I'll create separate video for unsorted array.

[@arijitmohapatra147]

What if the numbers in random order?

[@iamnew3353]

I think you have to sort the array before finding the pairs.

[@mujtabahussain7015]

@@iamnew3353 but in that case using hashset is more efficient i think.

[@jackelynmonteclaro2679]

How about unsorted array sir?

[@ProgrammingTutorials1M]

For unsorted array either you can use HashMap to find the pairs or you can first sort the array and then use two pointers approach to solve.

[@ProgrammingTutorials1M]

You can also check this tutorial for unsorted array - ruclips.net/video/MAjWstEJ8rM/видео.html

[@ketanmorey1953]

Having array element like{123,51,33,678,67} want such elements in output having digits sum is 6 ... Find such elements and put it into output array....so code please sir...

[@ProgrammingTutorials1M]

Hi Ketan, here is the code

[@ProgrammingTutorials1M]

public static void main(String[] args) {
int[] arr = {123,51,33,678,67};
int digitSum = 6;

for(int elem : arr) {
int sum = getSum(elem);
if(sum == digitSum) {
System.out.println(elem);
}
}
}
public static int getSum(int num) {
int sum = 0;
while(num > 0) {
int digit = num%10;
sum = sum + digit;
num = num/10;
}
return sum;
}

[@ketanmorey1953]

Thank u sir

[@ProgrammingTutorials1M]

@@ketanmorey1953 Please share this channel with your friends and colleagues.

[@yadnyeshrane7448]

Sir can i make use of 2 for loops..plz check whether the code is right
int arr[] = { 1, 2, 3, 4, 5, 6, 7 };
int k = 9;
for (int i = 0; i < arr.length; i++) {
for (int j = i + 1; j < arr.length; j++) {
if (arr[i] + arr[j] == k) {
System.out.println("pair is (" + arr[i] +" " +arr[j] + ")");
}
}
}

[@ProgrammingTutorials1M]

But the time complexity in this case will be O(n^2). Your code is correct only small modification is needed
int arr[] = { 1, 2, 3, 4, 5, 6, 7 };
int k = 9;
for (int i = 0; i < arr.length-1; i++) {
for (int j = i + 1; j < arr.length; j++) {
if (arr[i] + arr[j] == k) {
System.out.println("pair is (" + arr[i] +" " +arr[j] + ")");
}
}
}

[@merxxibeaucoup9093]

yes but what if there are duplicates numbers in the array??

[@technosys9060]

work only with sorted array

[@ProgrammingTutorials1M]

Yes, I have mentioned in title

[@start1learn-n171]

Tq

[@AlokBehera-n3k]

HI I need this probem fixed in java 8 .Could you please help me for this probem Given array : 1,3,5,7,9,11,16,20
Input value : 16
Output [2,5][3,4]
Write the logic to identify the pairs of index in given array which value sum equal to input value.I have pasted here the problem statement I need solution by using java 8 concepts.

[@prateekagrawal8166]

This won't work in test acse- a[]={ 1, 5, 7, -1, 5}, sum=6. its o/p should be 3 but this won't come with ur logic

[@ProgrammingTutorials1M]

This work only for sorted array.

[@jayugjklb9466]

Sprb

[@ProgrammingTutorials1M]

Thank you

[@thorunitha7755]

import java.io.*;
import java.util.*;
class Pair
{
public static void main(String args[])
{
int arr[]={30,5,10,20,35,40,45,25,15};
int sum=50;
for(int i=0;i

[@ProgrammingTutorials1M]

It's O(n^2). You can but it's not an efficient way.

[@thorunitha7755]

@@ProgrammingTutorials1M Thank you sir! This tutorial is really helpful for me.

[@sriracha9729]

Didnt consider duplicates

[@ProgrammingTutorials1M]

I have already mentioned in problem statement that array elements are distinct and in sorted order.

[@prashantsingh456]

your voice is low

[@ProgrammingTutorials1M]

In my new videos, you won't face this issue

[@Biharibabu135]

but 1+2+5=8 so it should print 1 2 5

[@zarifhossain515]

it's not a pair then