Given a string s, find the length of the longest substring without repeating characters.
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 * 104
s consists of English letters, digits, symbols and spaces.
Solutions
🧠 Cpp
class Solution {
public:
int lengthOfLongestSubstring(string s)
{
if(s.empty())
return 0;
int res = 0;
string substr = "";
for(char ch : s)
{
auto ch_in_res_indx = substr.find(ch);
if(ch_in_res_indx == std::string::npos)
substr.push_back(ch);
else
{
if(substr.size() > res)
res = substr.size();
substr.erase(substr.begin(), substr.begin()+ch_in_res_indx+1);
substr.push_back(ch);
}
}
if(substr.size() > res)
res = substr.size();
return res;
}
};