题目

Longest Valid Parentheses
Given a string containing just the characters ‘(‘ and ‘)’, find the length of the longest valid (well-formed) parentheses substring.

Example 1:

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Input: "(()"
Output: 2
Explanation: The longest valid parentheses substring is "
()"

Example 2:

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Input: ")()())"
Output: 4
Explanation: The longest valid parentheses substring is "()()"

题目

Longest Substring Without Repeating Characters
Given a string, find the length of the longest substring without repeating characters.

Example 1:

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Input: "abcabcbb"
Output: 3
Explanation: The answer is "abc", with the length of 3.

Example 2:

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Input: "bbbbb"
Output: 1
Explanation: The answer is "b", with the length of 1.

Example 3:

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Input: "pwwkew"
Output: 3
Explanation: The answer is "wke", with the length of 3.
             Note that the answer must be a substring, "pwke" is a subsequence and not a substring.

题目

AddTwoNumbers
You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.

You may assume the two numbers do not contain any leading zero, except the number 0 itself.

Example:

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Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
Explanation: 342 + 465 = 807.

题目

MajorityElementII
Given an integer array of size n, find all elements that appear more than ⌊ n/3 ⌋ times.

Note: The algorithm should run in linear time and in O(1) space.

• Example 1:

  1 2	Input: [3,2,3] Output: [3]

• Example 2:

  1 2	Input: [1,1,1,3,3,2,2,2] Output: [1,2]