add new solutions

solutions/0/q3/solution.go

@@ -0,0 +1,20 @@
+package q3
+
+func lengthOfLongestSubstring(s string) int {
+	seen := make([]bool, 256)
+	maxLen := 0
+
+	l := 0
+	for r := range len(s) {
+		c := s[r]
+		for seen[c] {
+			seen[s[l]] = false
+			l++
+		}
+		seen[c] = true
+		maxLen = max(maxLen, r-l+1)
+	}
+	return maxLen
+}
+
+var _ = lengthOfLongestSubstring