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Given the root of a binary tree and an integer targetSum, return true if the tree has a root-to-leaf path such that adding up all the values along the path equals targetSum. A leaf is a node with no children. Example 1: Input: root = [5,4,8,11,null,13,4,7,2,null,null,null,1], targetSum = 22 Output: true 재귀함수 사용하여 풀이 1. targetSum - 노드의 값이 0이면서 left, rigth가 null일 경우 -> 해당 케이스 존재 --> true 2. left n..

Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M. For example, 2 is written as II in Roman numeral, just two one's added together. 12 is written as XII, which is simply X + II. The number 27 is written as XXVII, which is XX + V + II. Roman numerals are usually written largest to smallest from left to right. However, the numeral for four is not IIII. Instead, the ..

Merge two sorted linked lists and return it as a sorted list. The list should be made by splicing together the nodes of the first two lists. 두개의 정렬된 연결 리스트를 합치고, 이를 정렬된 리스트로 반환해라. 이 리스트는 처음 2개의 리스트의 노드들을 함께 잘라이어 만들어라. Example 1: Constraints: The number of nodes in both lists is in the range [0, 50]. -100