LeetCode-in-All
3. Longest Substring Without Repeating Characters
Medium
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 * 104sconsists of English letters, digits, symbols and spaces.
Solution
/**
* @param {string} s
* @return {number}
*/
var lengthOfLongestSubstring = function (s) {
const lastIndices = new Array(256).fill(-1)
let maxLen = 0
let curLen = 0
let start = 0
for (let i = 0; i < s.length; i++) {
const cur = s.charCodeAt(i)
if (lastIndices[cur] < start) {
lastIndices[cur] = i
curLen++
} else {
const lastIndex = lastIndices[cur]
start = lastIndex + 1
curLen = i - start + 1
lastIndices[cur] = i
}
maxLen = Math.max(maxLen, curLen)
}
return maxLen
}
export { lengthOfLongestSubstring }