https://leetcode.com/problems/max-consecutive-ones-iii/submissions/

maxConsecutiveOnes.js

var longestOnes = function(A, K) {
    
    let result = 0;
    
    let i=0; let j=0; let k=K;
    while(j < A.length){
        if(A[j] === 1){
            result = Math.max(result, j-i+1);
            j++;
        }
        else if(k>0){
            result = Math.max(result, j-i+1);
            k--;
            j++;
        }else{
            if(A[i++] === 0) k++;
        }
    }
    
    return result;
    
};