silvergoni.builder()

https://leetcode.com/problems/hand-of-straights/ 1. 2022.02.05 시도 소요시간: 35분(11분 구상, 24분 코딩) class Solution { public boolean isNStraightHand(int[] hand, int groupSize) { if ((hand.length % groupSize) != 0) { return false; } // sort Arrays.sort(hand); List nums = new ArrayList(); List counts = new ArrayList(); int prev = -1; for (int i=0; i< hand.length; i++) { if (prev == hand[i]) { counts.set(co..

https://leetcode.com/problems/binary-tree-pruning/ 1. 2022.02.05 시도 소요시간: 5분 // dfs class Solution { public TreeNode pruneTree(TreeNode root) { root = dfs(root); return root; } public TreeNode dfs(TreeNode root) { if (root == null) { return null; } TreeNode left = dfs(root.left); if (left == null) { root.left = null; } TreeNode right = dfs(root.right); if (right == null) { root.right = null; } i..

https://leetcode.com/problems/find-largest-value-in-each-tree-row/ 1. 2022.01.30 시도 소요시간: 30분 이상(다른 일때문에 측정x) class Solution { public List largestValues(TreeNode root) { LinkedList output = new LinkedList(); if (root == null) { return output; } LinkedList queue = new LinkedList(); LinkedList depthQueue = new LinkedList(); queue.offer(root); depthQueue.offer(0); while(!queue.isEmpty()) { TreeNode..

https://leetcode.com/problems/3sum-closest/ 1. 2022.01.30 시도 소요시간: 27분(5분 구상, 22분 코딩) class Solution { public int threeSumClosest(int[] nums, int target) { Arrays.sort(nums); int output = 5000; for (int i=0; i subTarget) { sum = judgeSum(nums, subTarget, sum, temp); right--; } } output = judgeSum(nums, target, output, nums[i]+sum); } return output; } private int judgeSum(int[] nums, int target, ..

https://leetcode.com/problems/container-with-most-water/ 2. 2022.01.30 시도 소요시간: 4분 class Solution { public int maxArea(int[] height) { int left = 0; int right = height.length -1; int ret = 0; while (left < right) { int w = right - left; int h = Math.min(height[left], height[right]); ret = Math.max(ret, w * h); if (height[left] = e) { break; } area = Math.max(area, Math.min(height[s], height[e])*..

https://leetcode.com/problems/keys-and-rooms/ 1. 2022.01.30 시도 소요시간: 11분(3분 구상, 8분 코딩, recursive), 4분(앞서 구상, 4분 코딩, iterative) // recursive class Solution { public boolean canVisitAllRooms(List rooms) { if (rooms == null || rooms.size() == 0) { return true; } int roomSize = rooms.size(); boolean[] visited = new boolean[roomSize]; openDoor(0, rooms, visited); int counter =0; for (int i=0; i

https://leetcode.com/problems/robot-return-to-origin/ 1. 2022.01.27 시도 소요시간: 11분(3분 구상, 8분 코딩), 3분 class Solution { public boolean judgeCircle(String moves) { Map map = new HashMap(); map.put('U', 100000L); map.put('D', -100000L); map.put('L', 1L); map.put('R', -1L); long ret = 0; for(int i=0; i

https://leetcode.com/problems/middle-of-the-linked-list/ 1. 2022.01.24 시도 소요시간: 4분 class Solution { public ListNode middleNode(ListNode head) { if (head == null) { return null; } ListNode slow = head; ListNode fast = head.next; while(fast != null && fast.next != null) { slow = slow.next; fast = fast.next.next; } if (fast == null) { return slow; } return slow.next; } } 풀이 접근 과정 slow, fast로 하면 쉽게 ..

https://leetcode.com/problems/valid-palindrome/ 1. 2022.01.24 시도 소요시간: 7분(3분 구상, 4분 코딩, 공간복잡도O(n)), 11분(공간복잡도O(1)) // 공간복잡도: O(n) class Solution { public boolean isPalindrome(String s) { String filtered = ""; for(int x=0; x

https://leetcode.com/problems/reverse-string/ 1. 2022.01.24 시도 소요시간: 3분 class Solution { public void reverseString(char[] s) { for (int i=0; i