Mastery Points
0
Longest Substring Problem in dsa
Context & Logic
Finding the longest substring often refers to the 'Longest Substring Without Repeating Characters' problem, which is elegantly solved using the sliding window technique.
Example
function lengthOfLongestSubstring(s) {
let set = new Set();
let left = 0, maxLen = 0;
for (let right = 0; right < s.length; right++) {
while (set.has(s[right])) {
set.delete(s[left++]);
}
set.add(s[right]);
maxLen = Math.max(maxLen, right - left + 1);
}
return maxLen;
}Step-by-Step Logic
1
Maintain a sliding window defined by 'left' and 'right' pointers.
2
Use a Set to keep track of unique characters in the window.
3
Expand the window by moving 'right'.
4
If a character is already in the set, move 'left' until it's removed.
5
Calculate the window size at each step and keep the maximum.
Complexity Metrics
Time Efficiency
O(n)
Memory Footprint
O(k) where k is the character set size