Longest Subarray sum zero vs K

#1

In finding the longest subarray with zero-sum, we checked for arr[i]==0 (if a single element subarray is 0). But we are not doing that in the subarray sum to be k problem?

#2

@ankurguria hey that case is handled in when we use the map, suppose the sum till i-1 is a, now at i i encounter k, now pre will be a+k, on searching the map for “a+k-k” we will get “i-1” and subtracting it with i will give us 1.
If this resolves your doubt mark it as resolved.

#3

What if there is k at arr[0]; but we haven’t inserted 0 (as arr[0] - k == 0) in the map. We wouldn’t be updating the length to be 1. Am I right?

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#4

@Abhinav2604 if arr[0]=k, then pre also equals to k, now

if(pre==k) len=max(len,i+1);

will cause the updation of the length.
If this resolves your doubt mark it as resolved.

#5

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