INTUITION:

• Use two pointers, 'left' and 'right', to define the current substring.

• Use a vector 'mpp' as a hash map to store the last seen position of each character.

• Expand the window by moving the 'right' pointer and update the hash map.

• If a repeating character is found, move the 'left' pointer to exclude the previous occurrence.

• Keep track of the maximum length of non-repeating substring seen so far.

APPROACH:

• Use two pointers left and right to represent the current window of unique characters.
• Track the last index of each character using an array mpp of size 256.
• If s[right] is found within the window (left to right), move left to the index after its last occurrence.
• Calculate the length of the current window (right - left + 1) and update the maximum length.
• Continue until right reaches the end of the string and return the maximum length.

Time Complexity:O(N)

Space Complexity:O(N) where N represents the size of HashSet where we are storing our elements.

Here’s the code: