Given a string containing just the characters ‘(‘, ‘)’, ‘{‘, ‘}’, ‘[‘ and ‘]’, determine if the input string is valid. An input string is valid if: Open brackets must be closed by the same type of brackets.Open brackets must be closed in the correct order. Note that an empty string is also considered valid. Example 1: Input: “()” Output: true Example 2:…… Continue reading Leetcode 20 Valid Parentheses Java Solution
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Leetcode 3 Longest Substring Without Repeating Characters
Given a string, find the length of the longest substring without repeating characters. Example 1: Input: “abcabcbb” Output: 3 Explanation: The answer is “abc”, with the length of 3. Example 2: Input: “bbbbb” Output: 1 Explanation: The answer is “b”, with the length of 1. Example 3: Input: “pwwkew” Output: 3 Explanation: The answer is “wke”, with…… Continue reading Leetcode 3 Longest Substring Without Repeating Characters