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문제 https://leetcode.com/problems/data-stream-as-disjoint-intervals/description/ Data Stream as Disjoint Intervals - LeetCode Data Stream as Disjoint Intervals - Given a data stream input of non-negative integers a1, a2, ..., an, summarize the numbers seen so far as a list of disjoint intervals. Implement the SummaryRanges class: * SummaryRanges() Initializes the object with an e leetcode.com 주어진..

문제 https://leetcode.com/problems/cheapest-flights-within-k-stops/description/ Cheapest Flights Within K Stops - LeetCode Cheapest Flights Within K Stops - There are n cities connected by some number of flights. You are given an array flights where flights[i] = [fromi, toi, pricei] indicates that there is a flight from city fromi to city toi with cost pricei. You are also giv leetcode.com 최대 k +1..

문제 https://leetcode.com/problems/snakes-and-ladders/description/ Snakes and Ladders - LeetCode Snakes and Ladders - You are given an n x n integer matrix board where the cells are labeled from 1 to n2 in a Boustrophedon style [https://en.wikipedia.org/wiki/Boustrophedon] starting from the bottom left of the board (i.e. board[n - 1][0]) and alternati leetcode.com 알아야 할 개념 BFS 풀이 BFS 구현 문제이다. 풀이는 ..

문제 Bus Routes - LeetCode Bus Routes - LeetCode Bus Routes - You are given an array routes representing bus routes where routes[i] is a bus route that the ith bus repeats forever. * For example, if routes[0] = [1, 5, 7], this means that the 0th bus travels in the sequence 1 -> 5 -> 7 -> 1 -> 5 -> 7 -> 1 leetcode.com 버스 탄 총 횟수를 구하는 문제 알아야 할 개념 자바 인접 리스트 해시맵 HashMap 구조 https://0713k.tistory.com/30 ..

문제 https://leetcode.com/problems/number-of-islands/ Number of Islands - LeetCode Number of Islands - Given an m x n 2D binary grid grid which represents a map of '1's (land) and '0's (water), return the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may ass leetcode.com 주어진 2차원 배열에서 '1' 부분의 집합들의 개수를 리턴하는 문제 알아야 할 개념 ..

문제 https://leetcode.com/problems/single-number/description/ Single Number - LeetCode Single Number - Given a non-empty array of integers nums, every element appears twice except for one. Find that single one. You must implement a solution with a linear runtime complexity and use only constant extra space. Example 1: Input: nums = [2 leetcode.com 한 번만 등장하는 원소를 추출하자 필요한 개념 set 자료구조 XOR 연산 풀이 처음에 S..

문제 Restore IP Addresses - LeetCode 12)return ans; helper(s, "", 0, 0); return ans; } public void helper(String s, String cur_str,int level,int idx){ if(level == 4){ if(idx == s.length()) ans.add(cur_str.substring(0, cur_str.length()-1)); return; } for(int i =1 ;i 1 && temp_str.charAt(0) == '0' ) || getN(temp_str)..

문제 https://leetcode.com/problems/search-insert-position/description/ Search Insert Position - LeetCode Search Insert Position - Given a sorted array of distinct integers and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order. You must write an algorithm with O(log n) runtime com leetcode.com 이진 탐색을 할줄 아니? 물어보는 문제 풀이 정렬..