maxSubarraySum.js

function maxSubarraySum(arr,n){
 let max=0;
 let temp =0;
 // if(arr.length<n) return null;
 for (let i = 0; i < n; i++) {
 temp +=arr[i];
 }
 max=temp;
 for (let j = n; j < arr.length; j++) {
 max = max - arr[j-n] + arr[j];
 temp = Math.max(temp, max);
 
 }
 return temp;
}

// maxSubarraySum([100,200,300,400,500],2)//700
// maxSubarraySum([-3,4,0,-2,6,-1],2)//5
// maxSubarraySum([2,3],3)//null

maxSubarraySum([1,4,2,10,23,3,1,0,20],4)//39

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