Longest Substring Without Repeating Characters

PROBLEM

Given a string s, find the length of the longest substring without repeating characters.

Example1

*Input*: s = "abcabcbb"
*Output*: 3
Explanation: The answer is "abc", with the length of 3.

Example2

*Input*: s = "bbbbb"
*Output*: 1
Explanation: The answer is "b", with the length of 1.

Example3

*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.

SOLVING

Steps

Code

class Solution {
  class Solution {
  public:
    int lengthOfLongestSubstring(string s) {
      int string_size = s.length();
      int pointer = 0;
      int max_size = 0;
      int size;
      unordered_map<char, int> hash;

      while (pointer < string_size) {
	size = 0;
	hash.clear();
	while (pointer < string_size &&
	       hash.emplace(s[pointer], pointer).second) {
	  pointer++;
	  size++;
	}
	if (size > max_size) max_size = size;
	if (pointer < string_size) pointer = hash[s[pointer]] + 1;
      }
      return max_size;
    }
  };

PROBLEM