20181027

Author: fay111101

src/main/java/leetcode/array/_121_BestTimeToBuyAndSellStock.java

@@ -6,7 +6,7 @@
 (ie, buy one and sell one share of the stock),
  design an algorithm to find the maximum profit.
 */
-public class BestTimeToBuyAndSellStock {
+public class _121_BestTimeToBuyAndSellStock {
 
     public int maxProfit(int[] prices){
         if(prices==null||prices.length==0){

src/main/java/leetcode/array/_122_BestTimeToBuyAndSellStock2.java

@@ -8,7 +8,7 @@ transactions as you like (ie, buy one and sell one share of the stock multiple
  (ie, you must sell the stock before you buy again).
 */
 
-public class BestTimeToBuyAndSellStock2 {
+public class _122_BestTimeToBuyAndSellStock2 {
     public int maxProfit(int[] prices) {
         if(prices==null||prices.length==0){
             return 0;

src/main/java/leetcode/array/_153_FindMinimumInRotatedSortedArry.java

@@ -24,16 +24,18 @@ public int findMin(int[] nums) {
         if(nums==null||nums.length==0) return -1;
         int mid=0;
         int left=0,right=nums.length-1;
+        //控制nums[left]>=nums[right].使第一个指针永远指向第一个递增子区间，第二个指针永远指向第二个递增子区间
         while(nums[left]>=nums[right]&&left<right){
+            //第一个指针已经到达第一个子区间的末尾
             if(right-left==1){
                 mid=right;
                 break;
             }
             mid=(left+right)>>1;
             if(nums[mid]>nums[left]){
-                left=mid;
+                left=mid+1;
             }else{
-                right=mid;
+                right=mid-1;
             }
         }
 

src/main/java/leetcode/array/_15_Sum3.java

@@ -18,7 +18,7 @@ Elements in a triplet (a,b,c) must be in non-descending order. (ie, a ≤ b ≤
     (-1, 0, 1)
     (-1, -1, 2)
 */
-public class Sum3 {
+public class _15_Sum3 {
     public ArrayList<ArrayList<Integer>> threeSum(int[] num) {
         ArrayList<ArrayList<Integer>> result=new ArrayList<>();
         Arrays.sort(num);
@@ -55,7 +55,7 @@ public ArrayList<ArrayList<Integer>> threeSum(int[] num) {
         return  result;
     }
     public static void main(String[] args){
-        Sum3 test=new Sum3();
+        _15_Sum3 test=new _15_Sum3();
         int[] num={-1, 0 ,1 ,2 ,-1 ,-4};
         int[] num1={0,0,0,0};
         int[] num2={-2,0,1,1,2};

src/main/java/leetcode/array/_16_SumClosest.java

@@ -10,7 +10,7 @@
 
     The sum that is closest to the target is 2. (-1 + 2 + 1 = 2).
 */
-public class SumClosest {
+public class _16_SumClosest {
     public int threeSumClosest(int[] num, int target) {
         int closet=num[0]+num[1]+num[2];
         int diff=Math.abs(closet-target);

src/main/java/leetcode/array/_18_Sum4.java

@@ -21,7 +21,7 @@ Elements in a quadruplet (a,b,c,d) must be in non-descending order. (ie,
     (-2, -1, 1, 2)
     (-2,  0, 0, 2)
 */
-public class Sum4 {
+public class _18_Sum4 {
     public ArrayList<ArrayList<Integer>> fourSum(int[] num, int target) {
 
         //Set<ArrayList<Integer>> result = new TreeSet<>();
@@ -157,7 +157,7 @@ public static void main(String[] args){
         int[] arr1={-3,-2,-1,0,0,1,2,3};
         int[] arr2={-1,-5,-5,-3,2,5,0,4};
         int[] arr3={-1,0,-5,-2,-2,-4,0,1,-2};
-        Sum4 test=new Sum4();
+        _18_Sum4 test=new _18_Sum4();
        // ArrayList<ArrayList<Integer>> result1=test.fourSum1(arr2,-7);
         //有重复
         ArrayList<ArrayList<Integer>> result1=test.fourSum1(arr3,-9);

…e/dfsbfsbacktracing/_126_WordLadder.java …e/dfsbfsbacktracing/_127_WordLadder.javasrc/main/java/leetcode/dfsbfsbacktracing/_126_WordLadder.java renamed to src/main/java/leetcode/dfsbfsbacktracing/_127_WordLadder.java src/main/java/leetcode/dfsbfsbacktracing/_126_WordLadder.java renamed to src/main/java/leetcode/dfsbfsbacktracing/_127_WordLadder.java

@@ -3,7 +3,41 @@
 import java.util.HashSet;
 import java.util.LinkedList;
 
-public class _126_WordLadder {
+/**
+ *给定两个单词（beginWord 和 endWord）和一个字典，找到从 beginWord 到 endWord 的最短转换序列的长度。转换需遵循如下规则：
+ *
+ * 每次转换只能改变一个字母。
+ * 转换过程中的中间单词必须是字典中的单词。
+ * 说明:
+ *
+ * 如果不存在这样的转换序列，返回 0。
+ * 所有单词具有相同的长度。
+ * 所有单词只由小写字母组成。
+ * 字典中不存在重复的单词。
+ * 你可以假设 beginWord 和 endWord 是非空的，且二者不相同。
+ * 示例 1:
+ *
+ * 输入:
+ * beginWord = "hit",
+ * endWord = "cog",
+ * wordList = ["hot","dot","dog","lot","log","cog"]
+ *
+ * 输出: 5
+ *
+ * 解释: 一个最短转换序列是 "hit" -> "hot" -> "dot" -> "dog" -> "cog",
+ *      返回它的长度 5。
+ * 示例 2:
+ *
+ * 输入:
+ * beginWord = "hit"
+ * endWord = "cog"
+ * wordList = ["hot","dot","dog","lot","log"]
+ *
+ * 输出: 0
+ *
+ * 解释: endWord "cog" 不在字典中，所以无法进行转换。
+ */
+public class _127_WordLadder {
 
     public int ladderLength(String start, String end, HashSet<String> dict) {
         if (start == null || end == null || start.length() == 0 || end.length() == 0 || start.length() != end.length())

…ain/java/leetcode/search/WordSearch.java …de/dfsbfsbacktracing/_79_WordSearch.javasrc/main/java/leetcode/search/WordSearch.java renamed to src/main/java/leetcode/dfsbfsbacktracing/_79_WordSearch.java src/main/java/leetcode/search/WordSearch.java renamed to src/main/java/leetcode/dfsbfsbacktracing/_79_WordSearch.java

@@ -1,4 +1,4 @@
-package main.java.leetcode.search;
+package leetcode.dfsbfsbacktracing;
 
 /**
  *  Given a 2D board and a word, find if the word exists in the grid.
@@ -17,8 +17,26 @@
  word ="ABCCED", -> returnstrue,
  word ="SEE", -> returnstrue,
  word ="ABCB", -> returnsfalse.
+ 给定一个二维网格和一个单词，找出该单词是否存在于网格中。
+
+ 单词必须按照字母顺序，通过相邻的单元格内的字母构成，其中“相邻”单元格是那些水平相邻或垂直相邻的单元格。同一个单元格内的字母不允许被重复使用。
+
+ 示例:
+
+ board =
+ [
+ ['A','B','C','E'],
+ ['S','F','C','S'],
+ ['A','D','E','E']
+ ]
+
+ 给定 word = "ABCCED", 返回 true.
+ 给定 word = "SEE", 返回 true.
+ 给定 word = "ABCB", 返回 false.
+
  */
-public class WordSearch {
+public class _79_WordSearch {
+
     public boolean exist(char[][] board, String word) {
         if(board==null||board.length==0||board[0].length==0){
             return false;

…main/java/leetcode/dynamic/GrayCode.java …/java/leetcode/dpandgreedy/GrayCode.javasrc/main/java/leetcode/dynamic/GrayCode.java renamed to src/main/java/leetcode/dpandgreedy/GrayCode.java src/main/java/leetcode/dynamic/GrayCode.java renamed to src/main/java/leetcode/dpandgreedy/GrayCode.java

@@ -1,4 +1,4 @@
-package leetcode.dynamic;
+package leetcode.dpandgreedy;
 
 import java.util.ArrayList;
 

…java/leetcode/dynamic/SrambleString.java …/leetcode/dpandgreedy/SrambleString.javasrc/main/java/leetcode/dynamic/SrambleString.java renamed to src/main/java/leetcode/dpandgreedy/SrambleString.java src/main/java/leetcode/dynamic/SrambleString.java renamed to src/main/java/leetcode/dpandgreedy/SrambleString.java

@@ -1,4 +1,4 @@
-package main.java.leetcode.dynamic;
+package leetcode.dpandgreedy;
 
 /**
  * Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively.