Codility #11-MaxCounters

function solution(N, A) {

let prevMax = 0;

let maxCounter = 0;

let counters = Array(N).fill(0);

for (let i = 0, len = A.length; i < len; i++) {

if (A[i] <= N) {

let idx = A[i] - 1;

if (counters[idx] < prevMax) {

counters[idx] = prevMax + 1;

} else {

counters[idx]++;

}

if (maxCounter < counters[idx]) {

maxCounter = counters[idx];

}

} else {

prevMax = maxCounter;

}

}

for (let i = 0; i < N; i++) {

if (counters[i] < prevMax) {

counters[i] = prevMax;

}

}

return counters;

}