Two pointer / Sliding Window

1. Constant Window
2. Longest subarray / subsring wehere

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1. Constant Window

arr = [-1, 2, 3, 3, 4, 5, -1] k=4

consicutativly without kisping index

l=0
r=k-1

sum = 7

while r < n:
    sum = sum arr[l]
    l+=1
    r+=1
    sum = sum + arrr[r]
    maxsum = max(maxsum,sum)

2. Longest substring

arr = [2,5,1,7,10]

1. brrute force -> Generate all the subarray

maxlen = 0
for i in range(n):
    sum = 0
    for j in range(i,n):
        sum = sum + arr[j]
        if sum <=k:
            maxlen = max(maxlen , j-i+1)
        elif sum > k:
            break

prin(maxlen) 

2. better
3. optimal

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