Kindergarten adventure - HackerRank -study code - JavaScript - score 30 (maximum score 30)

kindergartenAdventure_studycode1.js

process.stdin.resume();
process.stdin.setEncoding('ascii');

var input_stdin = "";
var input_stdin_array = "";
var input_currentline = 0;

process.stdin.on('data', function (data) {
    input_stdin += data;
});

process.stdin.on('end', function () {
    input_stdin_array = input_stdin.split("\n");
    main();    
});

function readLine() {
    return input_stdin_array[input_currentline++];
}

/////////////// ignore above this line ////////////////////

function main() {
    var n = parseInt(readLine());

    var m = readLine().split(' ');
    m = m.map(Number);

    var add = [];
    var remove = [];
    for(var e=0; e<n; e++){
        if(m[e]>0){
            var s = e-m[e]+1;
            if(s<0){
                add[s+n] ? add[s+n]++ : add[s+n]=1;//console.log('s = '+(s+n));
                remove[n-1] ? remove[n-1]++ : remove[n-1]=1;//console.log('e = '+(n-1));
                s = 0;
            }
            add[s] ? add[s]++ : add[s]=1;//console.log('s = '+s);
            remove[e] ? remove[e]++ : remove[e]=1;//console.log('e = '+e);
        }
    }
    
    var x = add[0];
    var min = x;
    var minId = 1;
    for(var i=1; i<n; i++){
        if(remove[i-1]){
            x -= remove[i-1];
        }
        if(add[i]){
            x += add[i];
        }
        if(x<min){
            min = x;
            minId = i+1;
        }
    }

    console.log(minId);
}