Given an array A[] and a number x, check for pair in A[] with sum as x | GeeksforGeeks

This video is contributed by Harshit Jain.

[yazanshakhshir]

if i just knew this channel before going to my last interview i would have got the job :(
the interviewer asked me this question and i wasn't able to solve it using the hashmap method
i am very upset to find out how much easy the solution is :(

[hermesmercuriustrismegistu]

In Python you do not need to know the range of the hash map ie Python dictionary since they have dynamic sizes. I found Python to be a very useful language for coding interviews. Anyway thx a lot for the video!

[タクリス]

Wow!! Math and hashmap are two wonderful creation of the coding universe ❤️❤️❤️❤️❤️ thanks a lot! This is amazing 🤩🤩🤩🤩🤩🤩🤩🤩🤩🤩 I get the algorithm now

[wecan]

class Solution{
public:
// Function to check if array has 2 elements
// whose sum is equal to the given value
bool hasArrayTwoCandidates(int arr[], int n, int x)
{
map<int, int>mp;
for(int i=0;i<n;i++)
{
mp[arr[i]]++;
}
for(int i=0;i<n;i++)
{

{

{
return 1;
}
else if(x-arr[i]!=arr[i])
{
return 1;
}
}
}
return 0;
}
};

[akash]

what if sum value is -ve then how to solve using hashmap?

[divyansh]

I like the way u r teaching sir it's geat;

[rahulkumar-uwos]

sir what about sum=2 in the following example given at 0:26 using hashmap technique

[Sahil-explorer]

Using brute force approach we can do it too using two for loops but worst time is O(n^2).

[BtcTao]

the bool map will not work if there is repetitions in the array?

[sounavapal]

What about the extra space that we use for the hash array?

[nshukla]

With Hashing technique what if numbers are duplicate

[joydeepbhattacharjee]

The second method will never work if there is negative number in the given set of number (For C lang)

[simplybish]

binMap[arr[i]] = 1 ---> This line in code will throw index out of bound if the array has negative numbers.

[rapperstories]

Can someone explain third method i.e using remainders of the elements less than x....i couldnt find any video related to it

[mohammadmujahid]

Why u r using hasmap for second method, hashset is better here.

[axel]

In hash method the program not working

[combofriend]

I don't think hashmap solution works right of there are dups

[ravindrasutar]

i want to display those numbers in array..

[aakashmudigonda]

I didn't understand the second method

[marthamontes]

Damn i need to know wtf the sum is im in third im thinking about it so hard what about you give the awnser to the ppl???