JSFiddle - React, Tailwind, and code Playground

by moeishaa

JavaScript

const firstLast = (list, num) => {
	let i = 0,
   	j = list.length - 1;
    
  while (i < j && list[i] !== list[j]) {
  	if (list[i] !== num) i++;
    if (list[j] !== num) j--;
  }
  
  return [i, j];
};

let a = [1, 3, 5, 5, 5, 5 ,67, 123, 125],
	b = [1, 3, 5, 5, 5, 5 ,7, 123 ,125 ];

console.log(firstLast(a, 5));
console.log(firstLast(b, 7));