20231215 Finished

src/solution/mod.rs

@@ -3,3 +3,4 @@ mod s0009_palindrome_number;
 mod s0020_valid_parentheses;
 mod s2697_lexicographically_smallest_palindrome;
 mod s0002_add_two_numbers;
+mod s0003_longest_substring_without_repeating_characters;

src/solution/s0003_longest_substring_without_repeating_characters.rs

@@ -0,0 +1,74 @@
+/**
+ * [3] Longest Substring Without Repeating Characters
+ *
+ * Given a string s, find the length of the longest <span data-keyword="substring-nonempty">substring</span> without repeating characters.
+ *  
+ * <strong class="example">Example 1:
+ * 
+ * Input: s = "abcabcbb"
+ * Output: 3
+ * Explanation: The answer is "abc", with the length of 3.
+ * 
+ * <strong class="example">Example 2:
+ * 
+ * Input: s = "bbbbb"
+ * Output: 1
+ * Explanation: The answer is "b", with the length of 1.
+ * 
+ * <strong class="example">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.
+ * 
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.cn/problems/longest-substring-without-repeating-characters/
+// discuss: https://leetcode.cn/problems/longest-substring-without-repeating-characters/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+use std::cmp::max;
+use std::collections::HashSet;
+impl Solution {
+    pub fn length_of_longest_substring(s: String) -> i32 {
+        let chars: Vec<char> = s.chars().collect();
+        let mut window = HashSet::new();
+        let mut left = 0;
+        let mut result = 0;
+
+        for i in 0..chars.len() {
+            while window.contains(&chars[i]) {
+                window.remove(&chars[left]);
+                left += 1;
+            }
+
+            window.insert(chars[i]);
+            result = max(result, window.len());
+        }
+
+        result as i32
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_3() {
+        assert_eq!(3, Solution::length_of_longest_substring(String::from("abcabcbb")));
+        assert_eq!(1, Solution::length_of_longest_substring(String::from("bbbbb")));
+        assert_eq!(3, Solution::length_of_longest_substring(String::from("pwwkew")));
+    }
+}