본문 바로가기

전체 글137

Leetcode. Squares of a Sorted Array Problem: Given an array of integers A sorted in non-decreasing order, return an array of the squares of each number, also in sorted non-decreasing order. Example 1: Input: [-4,-1,0,3,10] Output: [0,1,9,16,100] Example 2: Input: [-7,-3,2,3,11] Output: [4,9,9,49,121] -Summary- Squares of each element in Array, then sort them using sort() function. class Solution: def sortedSquares(self, A: List[in.. 2020. 7. 4.
LeetCode. Arranging Coins Problem: You have a total of n coins that you want to form in a staircase shape, where every k-th row must have exactly k coins. Given n, find the total number of full staircase rows that can be formed. n is a non-negative integer and fits within the range of a 32-bit signed integer. -Summary- Solved using binary search. class Solution: def arrangeCoins(self, n: int) -> int: #k(k+1) // 2 2020. 7. 2.
Leetcode. Find Numbers with Even Number of Digits Problem: Given an array nums of integers, return how many of them contain an even number of digits. -Summary- 1. Format change int to string for each number and count the length of the str format of the number. 2. Check if it is even or odd number of digits. class Solution: def findNumbers(self, nums: List[int]) -> int: count = 0 for num in nums: if len(str(num)) % 2 == 0: count += 1 return coun.. 2020. 7. 1.
LeetCode. Unique Paths Problem: A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below). The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked 'Finish' in the diagram below). How many possible unique paths are there? Above is a 7 x 3 grid. How many possible unique paths are there? Example: -Cod.. 2020. 6. 30.
Leetcode. Max Consecutive Ones Problem: Given a binary array, find the maximum number of consecutive 1s in this array. Example 1: Input: [1,1,0,1,1,1] Output: 3 Explanation: The first two digits or the last three digits are consecutive 1s. The maximum number of consecutive 1s is 3. Note: The input array will only contain 0 and 1. The length of input array is a positive integer and will not exceed 10,000 class Solution: def fi.. 2020. 6. 29.
LeetCode. Sum Root to Leaf Numbers Problem: Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number. An example is the root-to-leaf path 1->2->3 which represents the number 123. Find the total sum of all root-to-leaf numbers. Note: A leaf is a node with no children. -Summary- Used recursive DFS. # Definition for a binary tree node. # class TreeNode: # def __init__(self, val=0, left=Non.. 2020. 6. 27.

티스토리툴바