3.longest-substring-without-repeating-characters.c

/*
 * @lc app=leetcode id=3 lang=c
 *
 * [3] Longest Substring Without Repeating Characters
 *
 * https://leetcode.com/problems/longest-substring-without-repeating-characters/description/
 *
 * algorithms
 * Medium (30.15%)
 * Likes:    9426
 * Dislikes: 567
 * Total Accepted:    1.6M
 * Total Submissions: 5.2M
 * Testcase Example:  '"abcabcbb"'
 *
 * Given a string, find the length of the longest substring without repeating
 * characters.
 *
 *
 * Example 1:
 *
 *
 * Input: "abcabcbb"
 * Output: 3
 * Explanation: The answer is "abc", with the length of 3.
 *
 *
 *
 * Example 2:
 *
 *
 * Input: "bbbbb"
 * Output: 1
 * Explanation: The answer is "b", with the length of 1.
 *
 *
 *
 * Example 3:
 *
 *
 * Input: "pwwkew"
 * Output: 3
 * Explanation: The answer is "wke", with the length of 3.
 * ⁠            Note that the answer must be a substring, "pwke" is a
 * subsequence and not a substring.
 *
 *
 *
 *
 *
 */

// @lc code=start
extern inline int max(int a, int b)
{
	return a > b ? a : b;
}

int lengthOfLongestSubstring(char *s)
{
	int hash[128] = {0};
	int maxCount = 0;
	int begin = 0;
	char ch;
	for (int i = 0; (ch = s[i]) != 0; i++)
	{
		begin = max(hash[ch], begin);
		maxCount = max(maxCount, i - begin + 1);
		hash[ch] = i + 1;
	}
	return maxCount;
}

// @lc code=end