Longest Substring Without Repeating Characters
Problem Statement - link #
Given a string s, find the length of the longest substring without repeating characters.
Examples #
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.
Example 4:
Input: s = ""
Output: 0
Constraints #
0 <= s.length <= 5 * 10^4sconsists of English letters, digits, symbols and spaces..
Solutions #
class Solution {
public:
int lengthOfLongestSubstring(string s) {
if(s.size() <= 1) return s.size();
unordered_map<char,int> mnk;
int cur=0,mx=0,left=0,right=0,i=0;
for(;i<s.size();i++){
if(mnk.count(s[i])==0) mnk.insert({s[i],i});
else {
if(mnk[s[i]]>=left)
left=mnk[s[i]]+1;
mnk[s[i]]=i;
}
right=i;
cur=right-left+1;
mx = max(mx,cur);
}
return mx;
}
};