To check if brackets are balanced in a string. Balanced brackets look like: “(())()”, “((()))”, “()”… Unbalanced brackets: “(((”, “())”, “(("

parenthesisChecker.go

package main

import "fmt"

// function to check if brackets are balanced
func isBalanced(expr string) bool {
	brackets := map[rune]rune{
		'(': ')',
		'[': ']',
		'{': '}',
	}
	stack := make([]rune, 0, len(expr))
	isBalanced := true

	for _, c := range expr {
		if _, ok := brackets[c]; ok == true {
			stack = append(stack, c)
		} else if len(stack) == 0 {
			isBalanced = false
			break
		} else if brackets[stack[len(stack)-1]] != c {
			isBalanced = false
			break
		} else {
			stack = stack[:len(stack)-1]
		}
	}

	if len(stack) != 0 {
		isBalanced = false
	}

	return isBalanced
}

// Driver code
func main() {
	// Function call
	fmt.Println(isBalanced(""))       // true (conditional ask the interviwer about this condition before start coding)
	fmt.Println(isBalanced("expr"))   // false
	fmt.Println(isBalanced("[(}]"))   // false
	fmt.Println(isBalanced("()"))     // true
	fmt.Println(isBalanced("[{()}]")) // true
}