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Given an array of size n, find the majority element. The majority element is the element that appears more than ⌊ n/2 ⌋ times. You may assume that the array is non-empty and the majority element always exist in the array. Example 1: Input: [3,2,3] Output: 3 Example 2: Input: [2,2,1,1,1,2,2] Output: 2 Solution class Solution: def majorityElement(self, nums: List[int]) -> int: keys = set(nums) ans..

We define the Perfect Number is a positive integer that is equal to the sum of all its positive divisors except itself.Now, given an integer n, write a function that returns true when it is a perfect number and false when it is not. Example: Input: 28 Output: True Explanation: 28 = 1 + 2 + 4 + 7 + 14 Note: The input number n will not exceed 100,000,000. (1e8) Solution import math class Solution(..

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 than or equal to k characters, then reverse the first k characters and left the other as original. Example: Input: s = "abcdefg", k = 2 Output: "bacdfeg" Rest..

Comparators are used to compare two objects. In this challenge, you'll create a comparator and use it to sort an array. The Player class is provided in the editor below. It has two fields: name : a string. score : an integer. Given an array of n Player objects, write a comparator that sorts them in order of decreasing score. If 2 or more players have the same score, sort those players alphabetic..

Given a non-negative integer c, your task is to decide whether there're two integers a and b such that a2 + b2 = c. Example 1: Input: 5 Output: True Explanation: 1 * 1 + 2 * 2 = 5 Example 2: Input: 3 Output: False Solution class Solution: def judgeSquareSum(self, c): for i in range(0,int(c**0.5)+1): extra=c-pow(i, 2) if (pow(int(extra**0.5),2)) == extra: return True return False SOMJANG/CODINGTE..

Given an array nums, write a function to move all 0's to the end of it while maintaining the relative order of the non-zero elements. Example: Input: [0,1,0,3,12] Output: [1,3,12,0,0] Note: You must do this in-place without making a copy of the array. Minimize the total number of operations. Solution class Solution: def moveZeroes(self, nums): for i in range(len(nums))[::-1]: if nums[i] == 0: nu..

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: Input: "()[]{}" Output: true Example 3: I..

Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. Note: For the purpose of this problem, we define empty string as valid palindrome. Example 1: Input: "A man, a plan, a canal: Panama" Output: true Example 2: Input: "race a car" Output: false Solution import re class Solution: def isPalindrome(self, s: str) -> bool: s = s.lower() text = ..

Given a string, find the first non-repeating character in it and return it's index. If it doesn't exist, return -1. Examples: s = "leetcode" return 0. s = "loveleetcode", return 2. Solution from collections import Counter class Solution: def firstUniqChar(self, s: str) -> int: answer = -1 s = list(s) cnt_dict = Counter(s) i = 0 for word in s: if cnt_dict[word] == 1: answer = i break i = i + 1 re..

Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array. Note: The number of elements initialized in nums1 and nums2 are m and n respectively. You may assume that nums1 has enough space (size that is greater or equal to m + n) to hold additional elements from nums2. Example: Input: nums1 = [1,2,3,0,0,0], m = 3 nums2 = [2,5,6], n = 3 Output: [1,2,2,3,5,6] Solut..

Given a non-empty array of integers, every element appears twice except for one. Find that single one. Note: Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory? Example 1: Input: [2,2,1] Output: 1 Example 2: Input: [4,1,2,1,2] Output: 4 Solution from collections import Counter class Solution: def singleNumber(self, nums: List[int]) -> int: c..

Write a program that outputs the string representation of numbers from 1 to n. But for multiples of three it should output “Fizz” instead of the number and for the multiples of five output “Buzz”. For numbers which are multiples of both three and five output “FizzBuzz”. Example: n = 15, Return: [ "1", "2", "Fizz", "4", "Buzz", "Fizz", "7", "8", "Fizz", "Buzz", "11", "Fizz", "13", "14", "FizzBuzz..

Given an array of integers A, consider all non-empty subsequences of A. For any sequence S, let the width of S be the difference between the maximum and minimum element of S. Return the sum of the widths of all subsequences of A. As the answer may be very large, return the answer modulo 10^9 + 7. Example 1: Input: [2,1,3] Output: 6 Explanation: Subsequences are [1], [2], [3], [2,1], [2,3], [1,3]..

We say that a string contains the word hackerrank if a subsequence of its characters spell the word hackerrank. For example, if string s = haacckkerrannkk it does contain hackerrank, but s = haacckkerannk does not. In the second case, the second r is missing. If we reorder the first string as hccaakkerrannkk, it no longer contains the subsequence due to ordering. More formally, let p[0], p[1], ...

Given an array containing n distinct numbers taken from 0, 1, 2, ..., n, find the one that is missing from the array. Example 1: Input: [3,0,1] Output: 2 Example 2: Input: [9,6,4,2,3,5,7,0,1] Output: 8 Note: Your algorithm should run in linear runtime complexity. Could you implement it using only constant extra space complexity? Solution class Solution: def missingNumber(self, nums: List[int]) -..

Write a function that reverses a string. The input string is given as an array of characters char[]. Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory. You may assume all the characters consist of printable ascii characters. Example 1: Input: ["h","e","l","l","o"] Output: ["o","l","l","e","h"] Example 2: Input: ["H","a","..

Given an integer, write a function to determine if it is a power of three. Example 1: Input: 27 Output: true Example 2: Input: 0 Output: false Example 3: Input: 9 Output: true Example 4: Input: 45 Output: false Follow up: Could you do it without using any loop / recursion? Solution class Solution: def isPowerOfThree(self, n: int) -> bool: return n > 0 and pow(3, 31, n) == 0 SOMJANG/CODINGTEST_PR..

Count the number of prime numbers less than a non-negative number, n. Example: Input: 10 Output: 4 Explanation: There are 4 prime numbers less than 10, they are 2, 3, 5, 7. Solution class Solution: def getPrimaryNum_Eratos(N): nums = [True] * (N + 1) for i in range(2, len(nums) // 2 + 1): if nums[i] == True: for j in range(i+i, N, i): nums[j] = False return [i for i in range(2, N) if nums[i] == ..

Given two integers dividend and divisor, divide two integers without using multiplication, division and mod operator. Return the quotient after dividing dividend by divisor. The integer division should truncate toward zero, which means losing its fractional part. For example, truncate(8.345) = 8 and truncate(-2.7335) = -2. Example 1: Input: dividend = 10, divisor = 3 Output: 3 Explanation: 10/3 ..

Given a collection of distinct integers, return all possible permutations. Example: Input: [1,2,3] Output: [ [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], [3,2,1] ] Solution from itertools import permutations class Solution: def permute(self, nums: List[int]) -> List[List[int]]: permu = list(permutations(nums, len(nums))) return permu SOMJANG/CODINGTEST_PRACTICE 1일 1문제 since 2020.02.07. Contribut..

Given an array with n objects colored red, white or blue, sort them in-place so that objects of the same color are adjacent, with the colors in the order red, white and blue. Here, we will use the integers 0, 1, and 2 to represent the color red, white, and blue respectively. Note: You are not suppose to use the library's sort function for this problem. Example: Input: [2,0,2,1,1,0] Output: [0,0,..

Implement pow(x, n), which calculates x raised to the power n (x^n). Example 1: Input: 2.00000, 10 Output: 1024.00000 Example 2: Input: 2.10000, 3 Output: 9.26100 Example 3: Input: 2.00000, -2 Output: 0.25000 Explanation: 2-2 = 1/22 = 1/4 = 0.25 Note: -100.0 float: my_pow_num = pow(x, n) if my_pow_num > (pow(2, 31) - 1): my_pow_num = pow(2, 31) -1 elif my_pow_num < (pow(2, 31)) * (-1): my_pow_nu..

1일 1문제 116일차! 오늘의 문제는 백준의 파도반 수열 입니다. 9461번: 파도반 수열 문제 오른쪽 그림과 같이 삼각형이 나선 모양으로 놓여져 있다. 첫 삼각형은 정삼각형으로 변의 길이는 1이다. 그 다음에는 다음과 같은 과정으로 정삼각형을 계속 추가한다. 나선에서 가장 긴 � www.acmicpc.net Solution loopNum = int(input()) nums = [] answer = [] for i in range(loopNum): inputNum = int(input()) nums.append(inputNum) for iN in nums: if iN

1일 1문제 115일차! 115일차의 문제는 제곱수의 합입니다. 1699번: 제곱수의 합 어떤 자연수 N은 그보다 작거나 같은 제곱수들의 합으로 나타낼 수 있다. 예를 들어 11=32+12+12(3개 항)이다. 이런 표현방법은 여러 가지가 될 수 있는데, 11의 경우 11=22+22+12+12+12(5개 항)도 가능하다 www.acmicpc.net Solution inputNum = int(input()) nc = [0] * (inputNum+1) for i in range(1, inputNum+1): nc[i] = i for j in range(1, i): if (j * j) > i: break nc[i] = min(nc[i], nc[i - j * j] + 1) print(nc[inputNum]) SO..

1일 1문제 114일차! 오늘의 문제는 백준의 진법 변환입니다. 2745번: 진법 변환 B진법 수 N이 주어진다. 이 수를 10진법으로 바꿔 출력하는 프로그램을 작성하시오. 10진법을 넘어가는 진법은 숫자로 표시할 수 없는 자리가 있다. 이런 경우에는 다음과 같이 알파벳 대문자를 www.acmicpc.net Solution B_jinbub_dic2 = { '0':0, '1':1, '2':2, '3':3, '4':4, '5':5, '6':6, '7':7, '8':8, '9':9, 'A':10, 'B':11, 'C':12, 'D':13, 'E':14, 'F':15, 'G':16, 'H':17, 'I':18, 'J':19, 'K':20, 'L':21, 'M':22, 'N':23, 'O':24, 'P':25, ..

1일 1문제 113일차! 오늘의 문제는 백준의 합분해 입니다. 2225번: 합분해 첫째 줄에 답을 1,000,000,000으로 나눈 나머지를 출력한다. www.acmicpc.net Solution inputNums = input() inputNums = inputNums.split() N = int(inputNums[0]) K = int(inputNums[1]) nc = [[0]*(N+1) for _ in range(K+1)] nc[0][0] = 1 # nc[0][0] = 1 for i in range(1, K+1): for j in range(0, N+1): nc[i][j] = nc[i-1][j] + nc[i][j-1] nc[i][j] = nc[i][j] % 1000000000 # print(nc) p..

1일 1문제 112일차! 오늘의 문제는 백준의 포도주 시식입니다. 2156번: 포도주 시식 효주는 포도주 시식회에 갔다. 그 곳에 갔더니, 테이블 위에 다양한 포도주가 들어있는 포도주 잔이 일렬로 놓여 있었다. 효주는 포도주 시식을 하려고 하는데, 여기에는 다음과 같은 두 가지 규 www.acmicpc.net Solution inputNum = int(input()) amount_of_wine = [] for i in range(inputNum): ryang = int(input()) amount_of_wine.append(ryang) nc = [[0]*3 for _ in range(inputNum+1)] for i in range(1, inputNum+1): nc[i][0] = max(nc[i-1]) ..

Your algorithms have become so good at predicting the market that you now know what the share price of Wooden Orange Toothpicks Inc. (WOT) will be for the next number of days. Each day, you can either buy one share of WOT, sell any number of shares of WOT that you own, or not make any transaction at all. What is the maximum profit you can obtain with an optimum trading strategy? For example, if ..

1일 1문제 110일차! 오늘의 문제는 SW Expert Academy의 홀수만 더하기 입니다. SW Expert Academy SW 프로그래밍 역량 강화에 도움이 되는 다양한 학습 컨텐츠를 확인하세요! swexpertacademy.com Solution T = int(input()) for i in range(T): numbers = list(map(int, input().split())) odd_nums = [num for num in numbers if num % 2 == 1] print("#{} {}".format(i+1, sum(odd_nums))) SOMJANG/CODINGTEST_PRACTICE 1일 1문제 since 2020.02.07. Contribute to SOMJANG/CODINGT..

1일 1문제 109일차! 오늘의 문제는 SW Expert Academy의 홀수일까 짝수일까입니다. SW Expert Academy SW 프로그래밍 역량 강화에 도움이 되는 다양한 학습 컨텐츠를 확인하세요! swexpertacademy.com Solution loop_num = int(input()) for i in range(loop_num): input_num = int(input()) if input_num % 2 == 0: print("#{} Even".format(i+1)) elif input_num % 2 == 1: print("#{} Odd".format(i+1)) SOMJANG/CODINGTEST_PRACTICE 1일 1문제 since 2020.02.07. Contribute to SOMJA..