[donghyeon95] Week 12

remove-nth-node-from-end-of-list/donghyeon95.java

@@ -0,0 +1,37 @@
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Queue;
+
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ *     int val;
+ *     ListNode next;
+ *     ListNode() {}
+ *     ListNode(int val) { this.val = val; }
+ *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
+ * }
+ */
+class Solution {
+	public ListNode removeNthFromEnd(ListNode head, int n) {
+		ArrayList<ListNode> list = new ArrayList<>();
+		ListNode nhead = head;
+
+		while (nhead != null) {
+			list.add(nhead);
+			nhead = nhead.next;
+		}
+
+		int size = list.size();
+
+		if (size == n) {
+			return head.next;
+		}
+
+		list.get(size - n - 1).next = list.get(size - n).next;
+
+		return head;
+	}
+}
+

same-tree/donghyeon95.java

@@ -0,0 +1,60 @@
+import java.util.LinkedList;
+import java.util.Queue;
+
+/**
+ * Definition for a binary tree node.
+ * public class TreeNode {
+ *     int val;
+ *     TreeNode left;
+ *     TreeNode right;
+ *     TreeNode() {}
+ *     TreeNode(int val) { this.val = val; }
+ *     TreeNode(int val, TreeNode left, TreeNode right) {
+ *         this.val = val;
+ *         this.left = left;
+ *         this.right = right;
+ *     }
+ * }
+ */
+class Solution {
+	public boolean isSameTree(TreeNode p, TreeNode q) {
+		// 트리 순회를 한다
+		// 현재 순회한 값이 다르다면 return false
+		if (p==null && q==null) return true;
+		if (p==null && q!=null) return false;
+		if (p!=null && q==null) return false;
+
+		Queue<TreeNode> pQue = new LinkedList<>();
+		pQue.add(p);
+		Queue<TreeNode> qQue = new LinkedList<>();
+		qQue.add(q);
+
+		while (!pQue.isEmpty() && !qQue.isEmpty()) {
+			TreeNode pNode = pQue.poll();
+			TreeNode qNode = qQue.poll();
+
+			if (pNode.val != qNode.val) return false;
+			if (pNode.left!=null && qNode.left!=null) {
+				pQue.add(pNode.left);
+				qQue.add(qNode.left);
+			} else if (pNode.left==null && qNode.left!=null) {
+				return false;
+			} else if (pNode.left!=null && qNode.left==null) {
+				return false;
+			}
+
+			if (pNode.right!=null && qNode.right!=null) {
+				pQue.add(pNode.right);
+				qQue.add(qNode.right);
+			} else if (pNode.right==null && qNode.right!=null) {
+				return false;
+			} else if (pNode.right!=null && qNode.right==null) {
+				return false;
+			}
+		}
+
+		return pQue.isEmpty() && qQue.isEmpty();
+
+	}
+}
+