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JohnnyHuoJohnnyHuo
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added a few questions
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‎.DS_Store

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‎src/countCompleteTreeNodes/Solution.java

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package countCompleteTreeNodes;
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/**
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* Definition for a binary tree node.
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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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*/
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public class Solution {
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public int countNodes(TreeNode root) {
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int res = 0;
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TreeNode node = root;
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while(node != null){
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res++;
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// int leftDepth = getDepth(root.left);
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// int rightDepth = getDepth(root.right);
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int leftDepth = getDepth(node.left);
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int rightDepth = getDepth(node.right);
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if(leftDepth == rightDepth){
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res = leftDepth == 0 ? res : res + (1 << leftDepth) - 1;
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node = node.right;
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}else{
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res = rightDepth == 0 ? res : res + (1 << rightDepth) - 1;
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node = node.left;
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}
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}
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return res;
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}
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public int getDepth(TreeNode root){
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if(root == null)
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return 0;
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return getDepth(root.left) + 1;
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}
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}

‎src/countCompleteTreeNodes/Test.java

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package countCompleteTreeNodes;
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public class Test {
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public static void main(String[] args){
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TreeNode root = new TreeNode(1);
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TreeNode left = new TreeNode(2);
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TreeNode right = new TreeNode(3);
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root.left = left;
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root.right = right;
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Solution sol = new Solution();
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System.out.println(sol.countNodes(root));
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System.out.println(sol.getDepth(root));
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System.out.println(sol.getDepth(left));
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System.out.println(sol.getDepth(right));
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}
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}

‎src/countCompleteTreeNodes/TreeNode.java

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package countCompleteTreeNodes;
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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) {
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val = x;
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}
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}

‎src/courseScheduleII/Solution.java

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package courseScheduleII;
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import java.util.*;
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public class Solution {
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public int[] findOrder(int numCourses, int[][] prerequisites) {
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int[] res = new int[numCourses];
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if(prerequisites == null){
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return null;
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}
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Map<Integer, Integer> indegree = new HashMap<Integer, Integer>();
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Map<Integer, ArrayList<Integer>> map = new HashMap<Integer, ArrayList<Integer>>();
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for(int i = 0; i < prerequisites.length; i++){
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for(int j = 0; j < prerequisites[0].length; j++){
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// prerequisites[i][j], j --> i, indegree of i + 1
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if(!indegree.containsKey(i)){
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indegree.put(i, 1);
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}else{
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indegree.put(i, indegree.get(i) + 1);
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}
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if(!map.containsKey(j)){
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// assume no duplicate pairs
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ArrayList<Integer> val = new ArrayList<Integer>();
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val.add(i);
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map.put(j, val);
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}else{
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map.get(j).add(i);
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}
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}
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}
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Queue<Integer> queue = new LinkedList<Integer>();
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for(int k = 0; k < numCourses; k++){
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// if(!map.containsKey(k)){
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if(indegree.get(k) == null){
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queue.offer(k);
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}
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}
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int index = 0;
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while(!queue.isEmpty()){
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int cur = queue.poll();
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res[index++] = cur;
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if(map.containsKey(cur)){
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ArrayList<Integer> neighbors = map.get(cur);
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for(Integer in : neighbors){
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if(indegree.containsKey(in)){
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indegree.put(in, indegree.get(in) - 1);
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if(indegree.get(in) == 0){
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queue.offer(in);
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}
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}
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}
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}
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}
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return res;
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}
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}

‎src/courseScheduleII/Test.java

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package courseScheduleII;
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public class Test {
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}

‎src/threeSum/Solution.java

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package threeSum;
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import java.util.*;
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public class Solution {
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public static List<List<Integer>> threeSum(int[] nums) {
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List<List<Integer>> res = new ArrayList<List<Integer>>();
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if(nums == null || nums.length == 0)
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return res;
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Arrays.sort(nums);
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int i = nums.length - 1;
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while(i >= 2){
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if(i != nums.length - 1 && nums[i] == nums[i + 1]){
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continue;
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}
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List<List<Integer>> curRes = twoSum(nums, i - 1, -nums[i]);
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for(int j = 0; j < curRes.size(); j++){
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curRes.get(j).add(nums[i]);
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}
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res.addAll(curRes);
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i--;
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}
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return res;
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}
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private static List<List<Integer>> twoSum(int[] sums, int end, int target){
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List<List<Integer>> result = new ArrayList<List<Integer>>();
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if(sums == null || sums.length == 0)
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return result;
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int left = 0;
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int right = end;
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while(left < right){
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if(sums[left] + sums[right] == target){
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List<Integer> curList = new ArrayList<Integer>();
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curList.add(sums[left]);
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curList.add(sums[right]);
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result.add(curList);
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left++;
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right--;
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while(left < end && sums[left] == sums[left - 1]){
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left++;
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}
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while(right > 0 && sums[right] == sums[right + 1]){
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right--;
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}
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}else if(sums[left] + sums[right] > target){
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right--;
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}else{
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left++;
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}
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}
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return result;
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}
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public static void main(String[] args){
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int[] input = new int[]{0,0,0,0};
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List<List<Integer>> res = threeSum(input);
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System.out.print(res.toString());
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}
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}

‎src/wildcardMatching/DpSolution.java

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package wildcardMatching;
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public class DpSolution {
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public boolean isMatch(String s, String p) {
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if(p.length()==0)
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return s.length()==0;
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boolean[] res = new boolean[s.length()+1];
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res[0] = true;
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for(int j=0;j<p.length();j++)
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{
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if(p.charAt(j)!='*')
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{
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for(int i=s.length()-1;i>=0;i--)
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{
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res[i+1] = res[i]&&(p.charAt(j)=='?'||s.charAt(i)==p.charAt(j));
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}
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}
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else
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{
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int i = 0;
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while(i<=s.length() && !res[i])
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i++;
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for(;i<=s.length();i++)
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{
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res[i] = true;
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}
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}
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res[0] = res[0]&&p.charAt(j)=='*';
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}
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return res[s.length()];
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}
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}

‎src/wildcardMatching/RecursiveSolution.java

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package wildcardMatching;
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public class RecursiveSolution {
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public boolean isMatch(String s, String p) {
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return isMatch(s, p, 0, 0);
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}
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private boolean isMatch(String s, String p, int i, int j){
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if(j == p.length())
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return i == s.length();
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// if current char at p is not *
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if(p.charAt(j) != '*'){
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if(i == s.length() || p.charAt(j) != s.charAt(i) && p.charAt(j) != '?'){
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return false;
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}else{
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return isMatch(s, p, i + 1, j + 1);
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}
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}else{
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// p.charAt(j) is '*', then three case :
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// 1), '*' == '', return isMatch(s, p, i, j + 1)
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// 2), '*' == '?', return isMatch(s, p, i + 1, j + 1)
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// 3), '*' == '?????' for i < s.length(), return isMatch(s, p, i, p + 1), i++
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// in summary, validate isMatch(s, p, i, j + 1) for [i, s.length())
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while(i < s.length() && (p.charAt(j) == s.charAt(i) || p.charAt(j) == '?')){
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if(isMatch(s, p, i, j + 1)){
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return true;
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}
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i++;
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}
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}
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return isMatch(s, p, i, j + 1); //consider this case : s is "aac", p is "a*b*"
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// return false;
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}
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}

‎src/wildcardMatching/Test.java

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package wildcardMatching;
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public class Test {
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public static void main(String[] args){
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RecursiveSolution rs = new RecursiveSolution();
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DpSolution dp = new DpSolution();
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String s = "aaac";
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String p = "a*b";
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System.out.println(rs.isMatch(s, p));
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System.out.println(dp.isMatch(s, p));
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System.out.println("Match s1");
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String s1 = "abbbbaaab";
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System.out.println(rs.isMatch(s1, p));
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System.out.println(dp.isMatch(s1, p));
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String s2 = "aabc";
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System.out.println("Match s2");
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System.out.println(rs.isMatch("aabc", "a*d"));
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System.out.println(dp.isMatch("aabc", "a*d"));
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System.out.println("Match s3");
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String s3 = "a";
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System.out.println(rs.isMatch(s3, p));
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System.out.println(dp.isMatch(s3, p));
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System.out.println("Match s4");
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String s4 = "abbaab";
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System.out.println(rs.isMatch(s4, p));
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System.out.println(dp.isMatch(s4, p));
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System.out.println("Match s5");
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String s5 = "ac";
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System.out.println(rs.isMatch(s5, p));
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System.out.println(dp.isMatch(s5, p));
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}
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}

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