Remove all elements from a linked list of integers that have value val.
Example:
Input: 1->2->6->3->4->5->6, val = 6
Output: 1->2->3->4->5SOLUTION
class Solution {
public ListNode removeElements(ListNode head, int val) {
ListNode current = head;
ListNode prev = null;
while(current!=null){
if(current.val ==val){
if(prev!=null){
prev.next = current.next;
current.next = null;
current = prev.next;
}else{
head = head.next;
current = current.next;
}
}
else{
prev = current;
current = current.next;
}
}
return head;
}
}
Runtime: 1 ms, faster than 87.14% of Java online submissions for Remove Linked List Elements.
Memory Usage: 40.1 MB, less than 87.67% of Java online submissions for Remove Linked List Elements.
public boolean isCompleteTree(TreeNode root) {
Queue<TreeNode> queue = new LinkedList<TreeNode>();
queue.add(root);
boolean isAbsent = false;
while(!queue.isEmpty()){
TreeNode node = queue.remove();
if(node==null){
isAbsent = true;
}else{
if(isAbsent){
return false;
}
queue.add(node.left);
queue.add(node.right);
}
}
return true;
}
public List<Integer> rightSideView(TreeNode root) {
return rightSideViewBFS(root);
}
private List<Integer> rightSideViewBFS(TreeNode root){
List<Integer> result = new ArrayList<Integer>();
if(root==null){
return result;
}
Queue<TreeNode> queue = new LinkedList<TreeNode>();
queue.add(root);
while(queue.size() != 0){
int size = queue.size();
for (int i=0; i<size; i++) {
TreeNode node = queue.remove();
if(i==0){
result.add(node.val);
}
if(node.right!=null){
queue.add(node.right);
}
if(node.left!=null){
queue.add(node.left);
}
}
}
return result;
}
/**
* 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 TreeNode sortedArrayToBST(int[] nums) {
return buildTree(0,nums.length-1,nums);
}
public TreeNode buildTree(int start, int end, int[] nums){
if(start>end){
return null;
}
int mid = (start+end)/2;
TreeNode root = new TreeNode(nums[mid]);
root.left = buildTree(start,mid-1,nums);
root.right = buildTree(mid+1,end,nums);
return root;
}
}
/**
* 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 int minDepth(TreeNode root) {
if(root==null){
return 0;
}
Queue<TreeNode> queue = new LinkedList<TreeNode>();
queue.add(root);
int level = 1;
int minDepth = 1000000000;
while(!queue.isEmpty()){
int size = queue.size();
for(int i=0;i<size;i++){
TreeNode node = queue.remove();
if(node!=null && node.left==null && node.right==null){
if(minDepth>level){
return level;
}
}else{
if(node.left!=null){
queue.add(node.left);
}
if(node.right!=null){
queue.add(node.right);
}
}
}
level ++;
}
return minDepth;
}
}
