kanrourou

//input: expression string, there may be multiple spaces
//return: reverse polish notation string with one space between each element
class Solution {
    public String convertToReversePolish(String exp) {
    	if (exp == null)
    		return null;
    	String res = "";
    	int len = exp.length();
    	Stack<Character> operator = new Stack<Character>(); 
    	Stack<String> reversePolish = new Stack<String>();

kanrourou

/**
 * Definition for undirected graph.
 * class UndirectedGraphNode {
 *     int label;
 *     List<UndirectedGraphNode> neighbors;
 *     UndirectedGraphNode(int x) { label = x; neighbors = new ArrayList<UndirectedGraphNode>(); }
 * };
 */
public class Solution {
    public UndirectedGraphNode cloneGraph(UndirectedGraphNode node) {

kanrourou

public class Solution {
    public int canCompleteCircuit(int[] gas, int[] cost) {
        if (gas == null || cost== null)
            return -1;
        int diff = 0;
        int len = gas.length;
        int start = 0;
        for (int i = 0; i <= 2 * len - 1; i++) {
            diff += (gas[i % len] - cost[i % len]);
            if (diff < 0) {

kanrourou

public class Solution {
    public boolean canJump(int[] A) {
        if (A == null)
            return false;
        int len = A.length;
        if (len == 0)
            return false;
        int rightBound = A[0];
        int i = 0;
        while (i <= rightBound) {

kanrourou

public class Solution {
    public boolean canJump(int[] A) {
        if (A == null)
            return false;
        int len = A.length;
        if (len == 0)
            return false;
        if (len == 1)
            return true;
        int gap = 1;

kanrourou

public class Solution {
    public int jump(int[] A) {
        if (A == null)
            return -1;
        int len = A.length;
        if (len == 0)
            return -1;
        if (len == 1)
            return 0;
        int rightBound = A[0];

kanrourou

/**
 * Definition for binary tree
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {

kanrourou

/**
 * Definition for binary tree
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {

kanrourou

/**
 * Definition for binary tree
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {

kanrourou

/**
 * Definition for binary tree
 * public class TreeNode {
 *     int val;
 *     TreeNode left;
 *     TreeNode right;
 *     TreeNode(int x) { val = x; }
 * }
 */
public class Solution {