Given a string s, find the length of the longest substring without repeating characters.
Test Cases
Example 1:
Input: s = "abcabcbb"
Output: 3
Explanation: The answer is "abc", with the length of 3.
Example 2:
Input: s = "bbbbb"
Output: 1
Explanation: The answer is "b", with the length of 1.
Example 3:
Input: s = "pwwkew"
Output: 3
Explanation: The answer is "wke", with the length of 3.
Notice that the answer must be a substring, "pwke" is a subsequence and not a substring.
Solution
class Solution {
public int lengthOfLongestSubstring(String s) {
Map<Character, Integer> map = new HashMap<>();
int start = 0, max = 0;
for(int i=0; i<s.length(); i++) {
if (map.containsKey(s.charAt(i))) {
start = Math.max(start, map.get(s.charAt(i))+1);
}
max = Math.max(max, i-start+1);
map.put(s.charAt(i), i);
}
return max;
}
}