MaxCounters.js

/*
  You are given N counters, initially set to 0, and you have two possible operations on them:
  
  • increase(X) − counter X is increased by 1,
  • max counter − all counters are set to the maximum value of any counter.
  
  A non-empty zero-indexed array A of M integers is given. This array represents consecutive operations:
  
  • if A[K] = X, such that 1 ≤ X ≤ N, then operation K is increase(X),
  • if A[K] = N + 1 then operation K is max counter.
  
  Write a function  that, given an integer N and a non-empty zero-indexed array A consisting of M integers, 
  returns a sequence of integers representing the values of the counters.
*/

function solution(N, A) {
    var j;
    var i;
    var len = A.length;
    var lastMax = 0;
    var max = 0; 
    var results = new Array (N);
    for(j = 0; j < N; j++) results[j] = 0;
  //Sets all of the preliminary array elements to 0
    var n1 = N + 1;
 //adds the number of Counters to N+1
    
    for(j=0; j < len; j++){
      //Option 1: where current number is less than counter max
        if(A[j] < n1){
          // i = value -1
            i = A[j] - 1;
          //sets the empty result counters to last max
            if (results[i] < lastMax){
              results[i] = lastMax;
            }
            results[i]++;
          //resets the max 
            if (max < results[i]){
              max = results[i];
            }
        //Option 2: Current number is greater than counter max (N+1)
        } else {
            lastMax = max;
        }
    }
    
  //lastMax is a 3rd party variable that sets the lastMax
  
    for(j = 0; j < N; j++){
      if (results[j] < lastMax) results[j] = lastMax;
    }
    
    return results;
}