add problem descriptions

fishercoder1534 · fishercoder1534 · commit adb91b1d026b · 2016-12-07T09:47:43.000-08:00
diff --git a/EASY/src/easy/BinaryTreePaths.java b/EASY/src/easy/BinaryTreePaths.java
@@ -1,15 +1,13 @@
 package easy;
 
+import classes.TreeNode;
+import utils.CommonUtils;
+
 import java.util.ArrayList;
 import java.util.List;
 
-import utils.CommonUtils;
-import classes.TreeNode;
-
-/**257. Binary Tree Paths  Question Editorial Solution  My Submissions
-Total Accepted: 59117
-Total Submissions: 191659
-Difficulty: Easy
+/**257. Binary Tree Paths
+ *
 Given a binary tree, return all root-to-leaf paths.
 
 For example, given the following binary tree:
diff --git a/EASY/src/easy/BullsandCows.java b/EASY/src/easy/BullsandCows.java
@@ -1,8 +1,20 @@
 package easy;
 
-import java.util.HashSet;
-import java.util.Set;
+/**You are playing the following Bulls and Cows game with your friend: You write down a number and ask your friend to guess what the number is. Each time your friend makes a guess, you provide a hint that indicates how many digits in said guess match your secret number exactly in both digit and position (called "bulls") and how many digits match the secret number but locate in the wrong position (called "cows"). Your friend will use successive guesses and hints to eventually derive the secret number.
 
+ For example:
+
+ Secret number:  "1807"
+ Friend's guess: "7810"
+ Hint: 1 bull and 3 cows. (The bull is 8, the cows are 0, 1 and 7.)
+ Write a function to return a hint according to the secret number and friend's guess, use A to indicate the bulls and B to indicate the cows. In the above example, your function should return "1A3B".
+
+ Please note that both secret number and friend's guess may contain duplicate digits, for example:
+
+ Secret number:  "1123"
+ Friend's guess: "0111"
+ In this case, the 1st 1 in friend's guess is a bull, the 2nd or 3rd 1 is a cow, and your function should return "1A1B".
+ You may assume that the secret number and your friend's guess only contain digits, and their lengths are always equal.*/
 public class BullsandCows {
 
     public String getHint(String secret, String guess) {
diff --git a/MEDIUM/src/medium/BinaryTreeZigzagLevelOrderTraversal.java b/MEDIUM/src/medium/BinaryTreeZigzagLevelOrderTraversal.java
@@ -1,13 +1,9 @@
-package easy;
-
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.LinkedList;
-import java.util.List;
-import java.util.Queue;
+package medium;
 
 import classes.TreeNode;
 
+import java.util.*;
+
 /**
  * 103. Binary Tree Zigzag Level Order Traversal  
  * 
diff --git a/README.md b/README.md
@@ -111,6 +111,7 @@
 |111|[Minimum Depth of Binary Tree](https://leetcode.com/problems/minimum-depth-of-binary-tree/)|[Solution](../../blob/master/EASY/src/easy/MinimumDepthofBinaryTree.java)| O(n)|O(1)~O(h) | Easy| BFS, DFS
 |110|[Balanced Binary Tree](https://leetcode.com/problems/balanced-binary-tree/)|[Solution](../../blob/master/EASY/src/easy/BalancedBinaryTree.java)| O(n)|O(1)~O(h) | Easy| DFS
 |107|[Binary Tree Level Order Traversal II](https://leetcode.com/problems/binary-tree-level-order-traversal-ii/)|[Solution](../../blob/master/EASY/src/easy/BinaryTreeLevelOrderTraversalII.java)| O(nlogn)|O(h) | Easy| BFS
+|103|[Binary Tree Zigzag Level Order Traversal](https://leetcode.com/problems/binary-tree-zigzag-level-order-traversal/)|[Solution](../../blob/master/EASY/src/easy/BinaryTreeZigzagLevelOrderTraversal.java)| O(n)|O(h) | Medium| BFS,DFS
 |102|[Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/)|[Solution](../../blob/master/EASY/src/easy/BinaryTreeLevelOrderTraversal.java)| O(n)|O(h) | Easy| BFS
 |91|[Decode Ways](https://leetcode.com/problems/decode-ways/)|[Solution](../../blob/master/MEDIUM/src/medium/DecodeWays.java)| O(n)|O(n) | Medium| DP
 |98|[Validate Binary Search Tree](https://leetcode.com/problems/validate-binary-search-tree/)|[Solution] | O(n) | O(1) | Medium | DFS/Recursion
