LeetCode/3.longest-substring-without-repeating-characters.cpp at master · samba9274/LeetCode · GitHub

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/*
 * @lc app=leetcode id=3 lang=cpp
 *
 * [3] Longest Substring Without Repeating Characters
 *
 * https://leetcode.com/problems/longest-substring-without-repeating-characters/description/
 *
 * algorithms
 * Medium (33.54%)
 * Likes:    26972
 * Dislikes: 1168
 * Total Accepted:    3.6M
 * Total Submissions: 10.8M
 * Testcase Example:  '"abcabcbb"'
 *
 * 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.
 *
 *
 *
 * Constraints:
 *
 *
 * 0 <= s.length <= 5 * 10^4
 * s consists of English letters, digits, symbols and spaces.
 *
 *
 */

// @lc code=start
class Solution
{
public:
    int lengthOfLongestSubstring(string s)
    {
        unordered_map<uint8_t, uint16_t> lookup;
        uint16_t start = 0, length = 0;
        for (uint16_t i = 0; i < s.length(); start = lookup.find(s[i]) != lookup.end() ? max(start, (uint16_t)(lookup[s[i]] + 1)) : start, lookup[s[i]] = i, length = max(length, (uint16_t)(i - start + 1)), i++)
            ;
        return length;
    }
};
// @lc code=end