기록하는 공간

/** * Example: * var ti = TreeNode(5) * var v = ti.`val` * Definition for a binary tree node. * class TreeNode(var `val`: Int) { * var left: TreeNode? = null * var right: TreeNode? = null * } */ class Solution { fun rangeSumBST(root: TreeNode?, L: Int, R: Int): Int { var result = 0 if (root == null) { return result } if (isbetween(root?.`val`, L, R)) { result += root?.`val` } result += rangeSumB..

class Solution { private fun swap (first: Int, second: Int, nums: IntArray) { val temp = nums[first] nums[first] = nums[second] nums[second] = temp } fun moveZeroes(nums: IntArray): Unit { var first = 0 var second = 0 val numsSize = nums.size while (first < numsSize) { if (nums[first] != 0) { swap(first, second, nums) second++ } first++ } } }

class Solution { fun wordPattern(pattern: String, str: String): Boolean { val strList = str.split(" ") if (pattern.length != strList.size) return false val map = mutableMapOf() for (i in strList.indices) { if (!map.containsValue(strList[i])) { map.put(pattern[i] , strList[i]) } } for (i in pattern.indices) { if (strList[i] != map.get(pattern[i])) { return false } } return true } }

class Solution { fun generate(numRows: Int): List { val totalArr: MutableList = mutableListOf() var innerArr: MutableList = mutableListOf(1) for (i in 0 until numRows) { totalArr.add(innerArr) val _innerArr: MutableList = mutableListOf() _innerArr.add(1) for (j in 0 until innerArr.size - 1) { _innerArr.add(innerArr[j] + innerArr[j +1 ]) } _innerArr.add(1) innerArr = _innerArr } return totalArr } }

class Solution { fun isSubsequence(s: String, t: String): Boolean { if (s == "") return true var pointS = 0 var pointT = 0 while (pointS < s.length && pointT < t.length) { if (s[pointS] == t[pointT]) { pointS++ } pointT++ } return pointS == s.length } }

class Solution { private fun swap(s: CharArray, left: Int, right: Int) { var temp = s[left] s[left] = s[right] s[right] = temp } fun reverseString(s: CharArray): Unit { var left = 0 var right = s.size - 1 while (left < right) { swap(s, left, right) left++ right-- } } }

class Solution { public TreeNode invertTree(TreeNode root) { if (root == null) return root; TreeNode node = root.left; root.left = root.right; root.right = node; invertTree(root.left); invertTree(root.right); return root; } }

class Solution { public boolean isPerfectSquare(int num) { if (num == 0 || num == 1) return true; long left = 1; long right = num / 2; long mid = 0; long nums = (long)num; while (left

substring 함수를 이용한 풀이 class Solution { private String takeOrtakeLast(int direction, int amount, String s) { int strLength = s.length(); if (direction == 0) { s = s.substring(amount, strLength) + s.substring(0 , amount); } else { s = (s.substring(strLength - amount, strLength) + s).substring(0, strLength); } return s; } public String stringShift(String s, int[][] shift) { for (int i = 0; i < shift..

Map을 이용한 풀이 class Solution { public int findDuplicate(int[] nums) { int duplicateNumber = 0; int numsLength = nums.length; Map map = new HashMap(); for (int i : nums) { map.put(i, map.getOrDefault(i, 0) + 1); if (map.get(i) > 1) duplicateNumber = i; } return duplicateNumber; } }