week1补充

zhangruihao.zhang · zhangruihao.zhang · commit 535fb1c3cbf4 · 2019-04-29T18:51:26.000+08:00
diff --git a/README.md b/README.md
@@ -17,6 +17,6 @@
 
 ## 注意事项
 
-1. **代码文件命名规则：**`LeetCode_题目序号_学号`，比如学号为 `0` 的学员完成 [LeetCode 的第 2 题](https://leetcode.com/problems/add-two-numbers/description/) 后，请将代码文件名保存为  `LeetCode_2_0.py` (假设你使用的是 Python 语言)。
+1. **代码文件命名规则：**`LeetCode_题目序号_学号`，比如学号为 `0` 的学员完成 [LeetCode_33_108 的第 2 题](https://leetcode.com/problems/add-two-numbers/description/) 后，请将代码文件名保存为  `LeetCode_2_0.py` (假设你使用的是 Python 语言)。
 2. **作业公布地址：** 我们会在置顶的 issue 中公布当周的算法练习题以及其他注意事项。
 3. 如果对 Git 和 GitHub 不太了解，请参考 [Git 官方文档](https://git-scm.com/book/zh/v2) 或者极客时间的[《玩转 Git 三剑客》](https://time.geekbang.org/course/intro/145)视频课程。
diff --git a/Week_01/id_108/LeetCode_20_108.java b/Week_01/id_108/LeetCode_20_108.java
@@ -0,0 +1,49 @@
+import org.junit.Test;
+
+import java.util.Stack;
+
+/**
+ * @author zhangruihao.zhang
+ * @version v1.0.0
+ * @since 2019/04/29
+ */
+public class LeetCode_20_108 {
+        public static void main(String[] args) {
+            String str = "()[]{}";
+            System.out.println(isValid(str));
+        }
+        public  static boolean isValid(String s) {
+            Stack stack = new Stack();
+            for(int i=0;i<s.length();i++){
+                char c = s.charAt(i);
+                if(stack.peek().equals(anotherChar(c))){
+                    stack.pop();
+                }else{
+                    stack.push(c);
+                }
+            }
+            return stack.isEmpty();
+        }
+
+        private static char anotherChar(char c){
+            if(c == '('){
+                return ')';
+            }
+            if(c == ')'){
+                return '(';
+            }
+            if(c == '{'){
+                return '}';
+            }
+            if(c == '}'){
+                return '{';
+            }
+            if(c == '['){
+                return ']';
+            }
+            if(c == ']'){
+                return '[';
+            }
+            return '0';
+        }
+}
diff --git a/Week_01/id_108/LeetCode_33_108.java b/Week_01/id_108/LeetCode_33_108.java
@@ -0,0 +1,75 @@
+/**
+ * @author zhangruihao.zhang
+ * @version v1.0.0
+ * @since 2019/04/29
+ */
+public class LeetCode_33_108 {
+    class Solution {
+        public int search(int[] nums, int target) {
+            if(nums == null || nums.length == 0){
+                return -1;
+            }
+
+            if(nums[0] == target){
+                return 0;
+            }
+            if(nums[nums.length - 1] == target){
+                return nums.length - 1;
+            }
+
+            int end = nums.length - 1;
+            int min = min(nums);
+            //如果没有旋转，并且最大的数小于target
+            if(min == 0 && nums[end]<target){
+                return -1;
+            }
+
+            if(nums[end] > target){
+                //target处于旋转的后半段
+                return binarySerach(nums,min,end,target);
+            }else{
+                //target有可能处于旋转的前半段
+                return binarySerach(nums,0,min-1,target);
+            }
+        }
+
+        //查找旋转点
+        private int min(int[] nums){
+            int low = 0;
+            int high = nums.length - 1;
+            int mid;
+            while(low < high){
+                mid = low + ((high-low)>>1);
+                if(nums[mid]>nums[high]){
+                    low = mid + 1;
+                }else{
+                    high = mid;
+                }
+            }
+            return low;
+        }
+
+        //二分查找
+        private int binarySerach(int[] nums,int left,int right,int target){
+            int mid = 0;
+            while(left<right){
+                mid = left + ((right - left)>>1);
+                if(nums[mid]==target){
+                    return mid;
+                }
+                if(nums[mid]<target){
+                    left = mid + 1;
+                    continue;
+                }
+                if(nums[mid]>target){
+                    right = mid - 1;
+                    continue;
+                }
+            }
+            if(nums[left] == target){
+                return left;
+            }
+            return -1;
+        }
+    }
+}
diff --git a/Week_01/id_108/LeetCode_503_108.java b/Week_01/id_108/LeetCode_503_108.java
@@ -0,0 +1,33 @@
+import java.util.Stack;
+
+/**
+ * @author zhangruihao.zhang
+ * @version v1.0.0
+ * @since 2019/04/29
+ */
+public class LeetCode_503_108 {
+    class Solution {
+        public int[] nextGreaterElements(int[] nums) {
+
+            Stack<Integer> stack = new Stack<>();
+            int index[] = new int[nums.length];
+            for (int i = 0; i < index.length; i++) {
+                index[i] = -1;
+            }
+            if (nums.length == 1) {
+                return index;
+            }
+            int count = 0;
+            while (count < 2) {
+                for (int i = 0; i < nums.length; i++) {
+                    while (!stack.isEmpty() && nums[i] > nums[stack.peek()]) {
+                        index[stack.pop()] = nums[i];
+                    }
+                    stack.push(i);
+                }
+                count++;
+            }
+            return index;
+        }
+    }
+}
diff --git a/Week_01/id_127/NOTE.md b/Week_01/id_127/NOTE.md
@@ -1,8 +1,8 @@
 # 学习笔记
 
-### LeetCode-83思路：
+### LeetCode_33_108-83思路：
 
 见图片: `83.jpeg`
 
-### LeetCode-21思路：
+### LeetCode_33_108-21思路：
 
