How to Compute the Number of Equivalent Domino Pairs?

  • 时间：2020-09-23 15:11:59
  • 分类：网络文摘
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Given a list of dominoes, dominoes[i] = [a, b] is equivalent to dominoes[j] = [c, d] if and only if either (a==c and b==d), or (a==d and b==c) – that is, one domino can be rotated to be equal to another domino. Return the number of p... ...

How to Multiply Two Matrices in C++?

  • 时间：2020-09-23 15:11:59
  • 分类：网络文摘
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Given two sparse matrices A and B, return the result of AB. You may assume that A’s column number is equal to B’s row number. Example: Input: 1 2 3 4 A = [   [ 1, 0, 0],   [-1, 0, 3] ] A = [ ... ...

How to Count the Path Sum from a Binary Tree using Depth First S

  • 时间：2020-09-23 15:11:59
  • 分类：网络文摘
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You are given a binary tree in which each node contains an integer value. Find the number of paths that sum to a given value. The path does not need to start or end at the root or a leaf, but it must go downwards (traveling only from paren... ...

The 24 Game Algorithm using Depth First Search

  • 时间：2020-09-23 15:11:59
  • 分类：网络文摘
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You have 4 cards each containing a number from 1 to 9. You need to judge whether they could operated through *, /, +, -, (, ) to get the value of 24. Example 1: Input: [4, 1, 8, 7] Output: True Explanation: (8-4) * (7-1) = 24 Example 2: In... ...

Algorithm to Construct Binary Tree from Preorder and Inorder Tra

  • 时间：2020-09-23 15:11:59
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Given preorder and inorder traversal of a tree, construct the binary tree. You may assume that duplicates do not exist in the tree. For example, given 1 2 preorder = [3,9,20,15,7] inorder = [9,3,15,20,7] preorder = [3,9,2... ...

How to Generate Parentheses using Bruteforce or Depth First Sear

  • 时间：2020-09-23 15:11:59
  • 分类：网络文摘
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Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: 1 2 3 4 5 6 7 [   "((()))",   "(()())",   "(... ...

String Algorithm: Reverse the first k characters for every 2k ch

  • 时间：2020-09-23 15:11:59
  • 分类：网络文摘
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Given a string and an integer k, you need to reverse the first k characters for every 2k characters counting from the start of the string. If there are less than k characters left, reverse all of them. If there are less than 2k but greater... ...

How to Find the K-diff Pairs in an Array with Two Pointer or Has

  • 时间：2020-09-23 15:11:59
  • 分类：网络文摘
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Given an array of integers and an integer k, you need to find the number of unique k-diff pairs in the array. Here a k-diff pair is defined as an integer pair (i, j), where i and j are both numbers in the array and their absolute differenc... ...

How to Find the Largest Unique Number in Array (C++)?

  • 时间：2020-09-23 15:11:59
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Given an array of integers A, return the largest integer that only occurs once. If no integer occurs once, return -1. Example 1: Input: [5,7,3,9,4,9,8,3,1] Output: 8 Explanation: The maximum integer in the array is 9 but it is repeated. Th... ...

How to Compute the N-th Tribonacci Number using Iterative Dynami

  • 时间：2020-09-23 15:11:59
  • 分类：网络文摘
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The Tribonacci sequence Tn is defined as follows: T0 = 0, T1 = 1, T2 = 1, and Tn+3 = Tn + Tn+1 + Tn+2 for n >= 0. Given n, return the value of Tn. Example 1: Input: n = 4 Output: 4 Explanation: T_3 = 0 + 1 + 1 = 2 T_4 = 1 + 1 + 2 = 4 E... ...