From baa9d15520727f418cfdd6cdf2b6efcff1989e23 Mon Sep 17 00:00:00 2001
From: YDZ <ydz627@gmail.com>
Date: Thu, 13 Jun 2019 08:46:07 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=20problem=2071?=
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---
 .../0071. Simplify Path/71. Simplify Path.go  | 35 +++++++++
 .../71. Simplify Path_test.go                 | 77 +++++++++++++++++++
 Algorithms/0071. Simplify Path/README.md      | 64 +++++++++++++++
 3 files changed, 176 insertions(+)
 create mode 100644 Algorithms/0071. Simplify Path/71. Simplify Path.go
 create mode 100644 Algorithms/0071. Simplify Path/71. Simplify Path_test.go
 create mode 100644 Algorithms/0071. Simplify Path/README.md

diff --git a/Algorithms/0071. Simplify Path/71. Simplify Path.go b/Algorithms/0071. Simplify Path/71. Simplify Path.go
new file mode 100644
index 00000000..5726957f
--- /dev/null
+++ b/Algorithms/0071. Simplify Path/71. Simplify Path.go	
@@ -0,0 +1,35 @@
+package leetcode
+
+import (
+	"path/filepath"
+	"strings"
+)
+
+// 解法一
+func simplifyPath(path string) string {
+	arr := strings.Split(path, "/")
+	stack := make([]string, 0)
+	var res string
+	for i := 0; i < len(arr); i++ {
+		cur := arr[i]
+		//cur := strings.TrimSpace(arr[i]) 更加严谨的做法应该还要去掉末尾的空格
+		if cur == ".." {
+			if len(stack) > 0 {
+				stack = stack[:len(stack)-1]
+			}
+		} else if cur != "." && len(cur) > 0 {
+			stack = append(stack, arr[i])
+		}
+	}
+	if len(stack) == 0 {
+		return "/"
+	} else {
+		res = strings.Join(stack, "/")
+	}
+	return "/" + res
+}
+
+// 解法二 golang 的官方库 API
+func simplifyPath_(path string) string {
+	return filepath.Clean(path)
+}
diff --git a/Algorithms/0071. Simplify Path/71. Simplify Path_test.go b/Algorithms/0071. Simplify Path/71. Simplify Path_test.go
new file mode 100644
index 00000000..65dd575a
--- /dev/null
+++ b/Algorithms/0071. Simplify Path/71. Simplify Path_test.go	
@@ -0,0 +1,77 @@
+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question71 struct {
+	para71
+	ans71
+}
+
+// para 是参数
+// one 代表第一个参数
+type para71 struct {
+	s string
+}
+
+// ans 是答案
+// one 代表第一个答案
+type ans71 struct {
+	one string
+}
+
+func Test_Problem71(t *testing.T) {
+
+	qs := []question71{
+
+		question71{
+			para71{"/.hidden"},
+			ans71{"/.hidden"},
+		},
+
+		question71{
+			para71{"/..hidden"},
+			ans71{"/..hidden"},
+		},
+
+		question71{
+			para71{"/abc/..."},
+			ans71{"/abc/..."},
+		},
+
+		question71{
+			para71{"/home/"},
+			ans71{"/home"},
+		},
+
+		question71{
+			para71{"/..."},
+			ans71{"/..."},
+		},
+
+		question71{
+			para71{"/../"},
+			ans71{"/"},
+		},
+
+		question71{
+			para71{"/home//foo/"},
+			ans71{"/home/foo"},
+		},
+
+		question71{
+			para71{"/a/./b/../../c/"},
+			ans71{"/c"},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 71------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans71, q.para71
+		fmt.Printf("【input】:%v       【output】:%v\n", p, simplifyPath(p.s))
+	}
+	fmt.Printf("\n\n\n")
+}
diff --git a/Algorithms/0071. Simplify Path/README.md b/Algorithms/0071. Simplify Path/README.md
new file mode 100644
index 00000000..085988d3
--- /dev/null
+++ b/Algorithms/0071. Simplify Path/README.md	
@@ -0,0 +1,64 @@
+# [71. Simplify Path](https://leetcode.com/problems/simplify-path/)
+
+## 题目
+
+Given an absolute path for a file (Unix-style), simplify it. Or in other words, convert it to the canonical path.
+
+In a UNIX-style file system, a period . refers to the current directory. Furthermore, a double period .. moves the directory up a level. For more information, see: Absolute path vs relative path in Linux/Unix
+
+Note that the returned canonical path must always begin with a slash /, and there must be only a single slash / between two directory names. The last directory name (if it exists) must not end with a trailing /. Also, the canonical path must be the shortest string representing the absolute path.
+
+
+
+Example 1:
+
+```c
+Input: "/home/"
+Output: "/home"
+Explanation: Note that there is no trailing slash after the last directory name.
+```
+
+Example 2:
+
+```c
+Input: "/../"
+Output: "/"
+Explanation: Going one level up from the root directory is a no-op, as the root level is the highest level you can go.
+```
+Example 3:
+
+```c
+Input: "/home//foo/"
+Output: "/home/foo"
+Explanation: In the canonical path, multiple consecutive slashes are replaced by a single one.
+```
+
+Example 4:
+
+```c
+Input: "/a/./b/../../c/"
+Output: "/c"
+```
+
+
+Example 5:
+
+```c
+Input: "/a/../../b/../c//.//"
+Output: "/c"
+```
+
+Example 6:
+
+```c
+Input: "/a//b////c/d//././/.."
+Output: "/a/b/c"
+```
+
+## 题目大意
+
+给出一个 Unix 的文件路径，要求简化这个路径。这道题也是考察栈的题目。
+
+## 解题思路
+
+这道题笔者提交了好多次才通过，并不是题目难，而是边界条件很多，没考虑全一种情况就会出错。有哪些边界情况就看笔者的 test 文件吧。
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