JSFiddle - React, Tailwind, and code Playground

JavaScript

let input = ['1,2,3,3,5'];


let print = this.print || console.log;
let gets = this.gets || ((arr, index) => () => arr[index++])(input, 0);


let inputOne = gets().split(',').map(Number);
 


let arr = [];
let arr2 = [];


for (let i = 0; i < input.length; i++) {
      arr2.push(i);
}





if (5 <= inputOne.length && inputOne.length <= 1000) {



for (let i = 1; i < inputOne.length; i++) {

          

        if (inputOne[i] != i) {

          print('input - ' + inputOne[i]);
          print('i - ' + i);


          arr.push(i);

        } 

}

}

print(arr.join(','));