Nested Loops and Slices in Go | CodeSignal Learn

Nested Loops and Slices in Go | CodeSignal Learn

Introduction

Welcome to our course on Mastering Implementation of Advanced Loops in Go! Are you ready for a challenging yet exciting task involving nested loops and slices ? We will be unraveling the skill of using nested loops to search through two slices. Brace yourself for a remarkable journey of practical learning. Let's get started!

Task Statement

Imagine a scenario where you are given two slices of integers. Your task is to write a function that retrieves and returns pairs of integers. The first item of the pair will be from the first slice, while the second one will come from the second slice. It's crucial to remember that the first element must be less than the second; that is, for every {i, j} pair, we want that i < j . The sequence of pairs in your output should align with the order they appear in the input slices. For instance, given the slices {1, 3, 7} and {2, 8, 9}, the function should return {{1, 2}, {1, 8}, {1, 9}, {3, 8}, {3, 9}, {7, 8}, {7, 9}} . In this case, the output does not include neither the pair {3, 2} nor the pair {7, 2}, because they don't respect the constraint that the first element must be less than the second. It will pose a challenge if no pairs exist or if any input slice is empty. Let's delve into this task step-by-step to uncover the solution!

Step 1 - Setting up the Initial Structure

Before venturing into the code, let's decode the problem. Nested looping fits perfectly here, as we need to to compare each element in slice1 with each element in slice2 . Start by creating an empty slice named result to store our pairs. We can use a slice of slices of integers for this purpose. Go package main func solution(slice1 []int, slice2 []int) [][]int {result := [][]int{} // More implementation will follow} Creating your function and data structure first is a wise strategy!

Step 2 - Implementing Nested Loops

Now, the focus turns to forming the nested loops. You need to iterate over both slices, and for this, you'll need nested loops. An outer loop will select one element from the first slice, and an inner loop will scan through each element of the second slice. Gopackage main func solution(slice1 []int, slice2 []int) [][]int { result := [][]int{} for _, i := range slice1 { for _, j := range slice2 { // Our logic goes here } } return result } In this setup, every element in slice1 is represented by i, and for each i, j represents an element in slice2.

Sign up

Join the 1M+ learners on CodeSignal

Be a part of our community of 1M+ users who develop and demonstrate their skills on CodeSignal

Step 3 - Incorporating the main Logic

With our loops ready, it's time to incorporate the logic. We run a check at this point: is the element i from slice1 less than the element j from slice2? If true, we append the pair {i, j} to our result slice. package main import "fmt" func solution(slice1 []int, slice2 []int) [][]int { result := [][]int{} for _, i := range slice1 { for _, j := range slice2 { if i < j { result = append(result, []int{i, j}) } } } return result } func main() { slice1 := []int{1, 3, 7} slice2 := []int{2, 8, 9} res := solution(slice1, slice2) for _, pair := range res { fmt.Printf("%d %d\n", pair[0], pair[1]) } } During each execution of our inner loop, we perform this check and store the pairs that comply with our condition.

Go

package main

import "fmt"

func solution(slice1 []int, slice2 []int) [][]int {
    result := [][]int{}
    for _, i := range slice1 {
        for _, j := range slice2 {
            if i < j {
                result = append(result, []int{i, j})
            }
        }
    }
    return result
}

func main() {
    slice1 := []int{1, 3, 7}
    slice2 := []int{2, 8, 9}
    res := solution(slice1, slice2)
    for _, pair := range res {
        fmt.Printf("%d %d\n", pair[0], pair[1])
    }
}