# Write a Golang program to find pairs with the given sum in an array(O(n))

## Examples

Input Array = [1, 3, 5, 7, 8, 9], sum = 11 => (3, 8)

## Approach to solve this problem

Step 1: Define a method that accepts an array and sum.

Step 2: Define a mapping variable, type map[int]int.

Step 3: Iterate the given array as i.

Step 4: If key in mapping sum-arr[i] is not present, then mapping[arr[i]]=i.

Step 5: If present, then print “pair is found”.

## Program

Live Demo

package main
import "fmt"
func findSumPair(arr []int, sum int){
mapping := make(map[int]int)
for i:=0; i<len(arr); i++{
if mapping[sum-arr[i]] == 0{
mapping[arr[i]] = i
} else {
fmt.Printf("Pair for given sum is (%d, %d).\n", arr[mapping[sum-arr[i]]], arr[i])
return
}
}
}

func main(){
findSumPair([]int{4, 3, 6, 7, 8, 1, 9}, 15)
findSumPair([]int{4, 3, 6, 7, 8, 1, 9}, 100)
}

## Output

Pair for given sum is (7, 8).
Pair not found in given array.

Updated on: 04-Feb-2021

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