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Commit 60b64d1

Browse files
Added some Easy questions 🎉
1 parent 8b39092 commit 60b64d1

40 files changed

+561
-23
lines changed

‎Easy/BalancedBinaryTree.java‎

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public class TreeNode {
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int val;
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TreeNode left;
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TreeNode right;
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TreeNode(int x) { val = x; }
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}
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class Solution {
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public boolean isBalanced(TreeNode root) {
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int left;
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int right;
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if(root == null)
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return true;
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left = height(root.left);
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right = height(root.right);
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if(Math.abs(left-right) <=1 && isBalanced(root.left) && isBalanced(root.right))
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return true;
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return false;
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}
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int height(TreeNode node)
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{
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/* base case tree is empty */
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if (node == null)
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return 0;
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/* If tree is not empty then height = 1 + max of left
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height and right heights */
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return 1 + Math.max(height(node.left), height(node.right));
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}
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}

‎Easy/StockBuySell.java‎ renamed to ‎Easy/BestTimeToBuyAndSellStock.java‎

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class StockBuySell {
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class Solution {
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public static void main(String[] args) {
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int[] arr = {7,1,5,3,6,4};
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System.out.println(maxProfit(arr));
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class TreeNode {
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int val;
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TreeNode left;
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TreeNode right;
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TreeNode(int x) { val = x; }
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}
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class ConvertSortedArrayToBinarySearchTree {
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public static void main(String[] args) {
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int[] nums = {-10,-3,0,5,9};
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TreeNode head = sortedArrayToBST(nums);
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System.out.println(head.val);
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/*System.out.println(head.val);
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System.out.println(head.left.val);
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System.out.println(head.left.right.val);
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System.out.println(head.right.val);
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System.out.println(head.right.right.val);
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*/
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}
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public static TreeNode sortedArrayToBST(int[] nums) {
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if(nums.length == 0)
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return null;
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return buildBST(nums, 0, nums.length - 1);
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}
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public static TreeNode buildBST(int[] nums, int start, int end) {
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if(start > end)
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return null;
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int mid = start + (end - start) / 2;
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TreeNode root = new TreeNode(nums[mid]);
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root.left = buildBST(nums, start, mid - 1);
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root.right = buildBST(nums, mid + 1, end);
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return root;
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}
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}

‎Easy/CountAndSay.class‎

-956 Bytes
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‎Easy/DistributeCandies.class‎

-1.16 KB
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‎Easy/ExcelSheetColumnNumber.java‎

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class Solution {
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public int titleToNumber(String s) {
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int result = 0;
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for (int i = 0; i < s.length(); i++){ //for s = A => 65-65=0 => Add 1 to it
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result *= 26; //For AA = 1*26 = 26 + 1 = 27
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result += ((s.charAt(i) - 'A') + 1);
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}
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return result;
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}
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}

‎Easy/FactorialTrailingZeroes.java‎

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class Solution{
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public int trailingZero(int n) { //Eg 25
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return n == 0 ? 0 : (n/2 + trailingZero(n/2));
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//25/2 = 5 + (25/2) => 5 + 1 = 6
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}
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}

‎Easy/HappyNumber.class‎

-894 Bytes
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‎Easy/HouseRobber.java‎

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class Solution {
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/* BEST SOLUTION
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TIME : O(n)
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SPACE: O(1)
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*/
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public int robEff(int[] nums) {
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if (nums.length == 0) return 0;
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int prev1 = 0;
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int prev2 = 0;
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for (int num : nums) {
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int tmp = prev1;
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prev1 = Math.max(prev2 + num, prev1);
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prev2 = tmp;
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}
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return prev1;
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}
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/* ANOTHER WAY */
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public int rob(int[] nums) { //Eg 2, 7 ,9 ,3 ,1
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int n = nums.length; //n=5
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return Math.max(nums[n-1], nums[n-2]); //Max(12,10) => return 12 correct ans
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}
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/* ANOTHER APPROACH */
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public int rob2(int[] nums) {
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if (nums.length == 0) return 0;

‎Easy/IntersectionOfTwoArray.class‎

-1.59 KB
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