Merge pull request #1 from algorithm004-01/master

更新第一周内容

Utils/git_quick_guide.md

@@ -0,0 +1,79 @@
+Environment Setup
+-----------------
+
+### Git Download
+```
+Download Git according to Windows, Linux, Mac
+```
+
+### Git global setup
+
+```
+git config --global user.name "Your Name"
+git config --global user.email "youremail@xxx"
+```
+
+### Add public key
+
+* Add your public key   
+Note: [Here](https://help.github.com/enterprise/2.15/user/articles/connecting-to-github-with-ssh) is the document about how to add the ssh key.
+
+
+Workflow with git
+-----------------
+
+
+### Prepare
+
+* Open (https://github.com/algorithm004-01/algorithm004-01) in your browser, and click "Fork", choose your own namespace.
+
+* Clone repo:
+
+	```
+	git clone https://github.com/your_namespace/algorithm004-01.git 
+	or
+	git clone git@github.com:your_namespace/algorithm004-01.git
+	```
+
+### Before developing a new homework
+
+1. Choose the base branch on group fork
+
+	```
+	git checkout master
+	```
+2. Write your own code
+
+
+### After developing
+
+1. Commit your changes in local repo.
+
+	```
+	git add /path/to/files/you/changed
+	git commit -m 'XXX submit xx homework code'
+	```
+
+
+### Merge your changes to `algorithm004-01/algorithm004-01`
+
+1. Push local commits to `your_namespace/algorithm004-01:mastr` in GitHub:
+
+	```
+	git push origin master
+	```
+
+2. Create pull request from XXX to `algorithm004-01/algorithm004-01:master`
+   ![step1](https://github.com/honeyaya/algorithm004-01/blob/master/Utils/pr1.png)
+   ![step2](https://github.com/honeyaya/algorithm004-01/blob/master/Utils/pr2.png)
+
+
+
+
+Appendix
+--------
+
+More Git Tutorial:
+- https://www.liaoxuefeng.com/wiki/896043488029600
+- 极客时间的git课程
+

Week 01/id_716/LeetCode_11_716.java

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+// package io.github.shniu.arts.training.week01;
+
+// https://leetcode-cn.com/problems/container-with-most-water/
+public class LeetCode_11_716 {
+
+    // 1. 暴力法, 时间复杂度高，O(n^2)
+    public int maxArea1(int[] height) {
+        int maxarea = 0;
+
+        for (int i = 0; i < height.length - 1; i++) {
+            for (int j = i + 1; j < height.length; j++) {
+                int minHeight = Math.min(height[i], height[j]);
+                maxarea = Math.max(maxarea, minHeight * (j - i));
+            }
+        }
+
+        return maxarea;
+    }
+
+    // 2. 双指针法
+    // 2.1 写法
+    public int maxArea21(int[] height) {
+        int maxarea = 0;
+
+        for (int left = 0, right = height.length - 1; left < right;) {
+            int minHeight = Math.min(height[left], height[right]);
+            maxarea = Math.max(maxarea, minHeight * (right - left));
+            // 看一下谁短就谁往里收缩一步
+            if (height[left] < height[right]) {
+                left++;
+            } else {
+                right--;
+            }
+        }
+
+        return maxarea;
+    }
+
+    // 2.2 2.1写法的改进版
+    public int maxArea22(int[] height) {
+        int maxarea = 0;
+
+        for (int left = 0, right = height.length - 1; left < right;) {
+            int minHeight = height[left] < height[right] ? height[left++] : height[right--];
+            // 注意这里要+1
+            maxarea = Math.max(maxarea, minHeight * (right - left + 1));
+        }
+
+        return maxarea;
+    }
+
+    // 2.3 更高效的写法
+    public int maxArea23(int[] height) {
+        int maxarea = 0;
+
+        for (int left = 0, right = height.length - 1; left < right;) {
+            int minHeight = Math.min(height[left], height[right]);
+            maxarea = Math.max(maxarea, minHeight * (right - left));
+
+            // 减少无用的面积计算次数，排除掉不需要计算的情况
+            while (height[left] <= minHeight && left < right) left++;
+            while (height[right] <= minHeight && left < right) right--;
+        }
+
+        return maxarea;
+    }
+}
+