2. Longest Substring Without Repeating Characters

Author: Sunjae95

longest-substring-without-repeating-characters/sunjae95.js

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+/**
+ * @description
+ * brainstorming:
+ * hash table + two pointer
+ *
+ * n = length of s
+ * time complexity: O(n)
+ * space complexity: O(n)
+ */
+var lengthOfLongestSubstring = function (s) {
+  const map = new Map();
+  let answer = 0;
+  let start = 0;
+  let end = 0;
+  for (let i = 0; i < s.length; i++) {
+    if (map.has(s[i])) start = Math.max(map.get(s[i]) + 1, start);
+    map.set(s[i], i);
+    end += 1;
+    answer = Math.max(answer, end - start);
+  }
+
+  return answer;
+};