20190317

Author: mJackie

code/lc33.java

@@ -6,7 +6,8 @@
  * 难度：Medium
  * 分类：Array, Binary Search
  * 思路：二分查找的思路，多了一步判断，判断哪部分有序，是否在这部分中
- * Tips：注意边界判断，是否有等号
+ * Tips：注意边界判断，是否有等号。挺麻烦的，没有输入样本，很难想通边边角角
+ *       lc81
  */
 public class lc33 {
     public static void main(String[] args) {
@@ -40,4 +41,26 @@ public static int search(int[] nums, int target) {
         }
         return -1;
     }
+
+    public int search2(int[] nums, int target) {
+        int begin = 0, end = nums.length-1;
+        while(begin<=end){
+            int mid = (begin+end)/2;
+            if(target==nums[mid]) return mid;
+            if(nums[begin]<=nums[mid]){  //左边有序，别忘了=，begin==end
+                if(target>=nums[begin]&&target<nums[mid]){
+                    end = mid-1;
+                }else{
+                    begin = mid+1;
+                }
+            }else{  //右边有序
+                if(target>nums[mid]&&target<=nums[end]){ //别忘了=
+                    begin = mid+1;
+                }else{
+                    end = mid-1;
+                }
+            }
+        }
+        return -1;
+    }
 }

code/lc81.java

@@ -0,0 +1,36 @@
+package code;
+/*
+ * 31. Search in Rotated Sorted Array II
+ * 题意：在翻转有序数组中查找指定数，数组中可能有相等的元素
+ * 难度：Medium
+ * 分类：Array, Binary Search
+ * 思路：多加了一种情况，就是 nums[mid]==nums[begin]==nums[end]
+ * Tips：注意边界判断，是否有等号
+ *       lc33
+ */
+public class lc81 {
+    public boolean search(int[] nums, int target) {
+        int begin = 0, end = nums.length-1;
+        while(begin<=end){
+            int mid = (begin+end)/2;
+            if(target==nums[mid]) return true;
+            if(nums[begin]==nums[end]&& nums[end]==nums[mid]) end--;
+            else if(nums[begin]<=nums[mid]){  //左边有序
+                if(target>=nums[begin]&&target<nums[mid]){
+                    end = mid-1;
+                }else{
+                    begin = mid+1;
+                }
+            }else if(nums[mid]<nums[end]){  //右边有序
+                if(target>nums[mid]&&target<=nums[end]){
+                    begin = mid+1;
+                }else{
+                    end = mid-1;
+                }
+            }else{
+                end--;
+            }
+        }
+        return false;
+    }
+}

readme.md

@@ -54,11 +54,13 @@ LeetCode 指南
 | 032 [Java](./code/lc32.java)
 | 033 [Java](./code/lc33.java)
 | 034 [Java](./code/lc34.java)
+| 034 [Java](./code/lc35.java)
 | 036 [Java](./code/lc36.java)
 | 038 [Java](./code/lc38.java)
 | 039 [Java](./code/lc39.java)
 | 041 [Java](./code/lc41.java)
 | 042 [Java](./code/lc42.java)
+| 043 [Java](./code/lc43.java)
 | 044 [Java](./code/lc44.java)
 | 046 [Java](./code/lc46.java)
 | 048 [Java](./code/lc48.java)