26 翻新了题解。

Author: aQua

Algorithms/0026.remove-duplicates-from-sorted-array/README.md

@@ -1,18 +1,50 @@
 # [26. Remove Duplicates from Sorted Array](https://leetcode.com/problems/remove-duplicates-from-sorted-array/)
 
 ## 题目
-Given a sorted array, remove the duplicates in place such that each element appear only once and return the new length.
 
-Do not allocate extra space for another array, you must do this in place with constant memory.
+Given a sorted array nums, remove the duplicates in-place such that each element appear only once and return the new length.
 
-For example,
-Given input array nums = [1,1,2],
+Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.
 
-Your function should return length = 2, with the first two elements of nums being 1 and 2 respectively. It doesn't matter what you leave beyond the new length.
+Example 1:
 
-## 解题思路
-题目要求原地删除重复的元素。并返回没有重复元素的切片的长度。
+```text
+Given nums = [1,1,2],
+
+Your function should return length = 2, with the first two elements of nums being 1 and 2 respectively.
+
+It doesn't matter what you leave beyond the returned length.
+```
+
+Example 2:
+
+```text
+Given nums = [0,0,1,1,1,2,2,3,3,4],
+
+Your function should return length = 5, with the first five elements of nums being modified to0, 1, 2, 3, and4 respectively.
+
+It doesn't matter what values are set beyondthe returned length.
+```
 
-## 总结
+Clarification:
 
+Confused why the returned value is an integer but your answer is an array?
+
+Note that the input array is passed in by reference, which means modification to the input array will be known to the caller as well.
+
+Internally you can think of this:
+
+```text
+// nums is passed in by reference. (i.e., without making a copy)
+int len = removeDuplicates(nums);
+
+// any modification to nums in your function would be known by the caller.
+// using the length returned by your function, it prints the first len elements.
+for (int i = 0; i < len; i++) {
+  print(nums[i]);
+}
+```
+
+## 解题思路
 
+见程序注释

Algorithms/0026.remove-duplicates-from-sorted-array/remove-duplicates-from-sorted-array.go

@@ -1,22 +1,13 @@
 package problem0026
 
-func removeDuplicates(nums []int) int {
-	if len(nums) <= 1 {
-		return len(nums)
-	}
-
-	res := 1
-	i := 1
-	for ; i < len(nums); i++ {
-		if nums[i] == nums[i-1] {
+func removeDuplicates(a []int) int {
+	left, right, size := 0, 1, len(a)
+	for ; right < size; right++ {
+		if a[left] == a[right] {
 			continue
 		}
-		if res != i {
-			nums[res] = nums[i]
-		}
-
-		res++
+		left++
+		a[left], a[right] = a[right], a[left]
 	}
-
-	return res
+	return left + 1
 }

Algorithms/0026.remove-duplicates-from-sorted-array/remove-duplicates-from-sorted-array_test.go

@@ -7,47 +7,38 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-type question struct {
-	para
-	ans
+// tcs is testcase slice
+var tcs = []struct {
+	nums []int
+	ans  int
+}{
+
+	{
+		[]int{1, 1, 2},
+		2,
+	},
+
+	{
+		[]int{0, 0, 1, 1, 1, 2, 2, 3, 3, 4},
+		5,
+	},
+
+	// 可以有多个 testcase
 }
 
-// para 是参数
-// one 代表第一个参数
-type para struct {
-	one []int
-}
-
-// ans 是答案
-// one 代表第一个答案
-type ans struct {
-	one int
-	two []int
-}
-
-func Test_Problem0026(t *testing.T) {
+func Test_removeDuplicates(t *testing.T) {
 	ast := assert.New(t)
 
-	qs := []question{
-
-		question{
-			para{[]int{1, 2, 2, 3, 3, 4, 5}},
-			ans{5, []int{1, 2, 3, 4, 5}},
-		},
-
-		question{
-			para{[]int{1}},
-			ans{1, []int{1}},
-		},
-
-		// 如需多个测试，可以复制上方元素。
+	for _, tc := range tcs {
+		fmt.Printf("~~%v~~\n", tc)
+		ast.Equal(tc.ans, removeDuplicates(tc.nums), "输入:%v", tc)
 	}
+}
 
-	for _, q := range qs {
-		a, p := q.ans, q.para
-		fmt.Printf("~~%v~~\n", p)
-		l := removeDuplicates(p.one)
-		ast.Equal(a.one, l, "输入:%v", p)
-		ast.Equal(a.two, p.one[:l])
+func Benchmark_removeDuplicates(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for _, tc := range tcs {
+			removeDuplicates(tc.nums)
+		}
 	}
 }

leetcode.json

@@ -1,7 +1,7 @@
 {
 	"Username": "aQuaYi",
-	"Ranking": 1089,
-	"Updated": "2018-05-21T17:08:00.86638057+08:00",
+	"Ranking": 1070,
+	"Updated": "2018-05-22T13:25:37.766569899+08:00",
 	"Record": {
 		"Easy": {
 			"Solved": 169,
@@ -325,7 +325,7 @@
 			"ID": 25,
 			"Title": "Reverse Nodes in k-Group",
 			"TitleSlug": "reverse-nodes-in-k-group",
-			"PassRate": "31%",
+			"PassRate": "32%",
 			"Difficulty": "Hard",
 			"IsAccepted": true,
 			"IsPaid": false,
@@ -4585,7 +4585,7 @@
 			"ID": 380,
 			"Title": "Insert Delete GetRandom O(1)",
 			"TitleSlug": "insert-delete-getrandom-o1",
-			"PassRate": "40%",
+			"PassRate": "39%",
 			"Difficulty": "Medium",
 			"IsAccepted": true,
 			"IsPaid": false,
@@ -8125,7 +8125,7 @@
 			"ID": 675,
 			"Title": "Cut Off Trees for Golf Event",
 			"TitleSlug": "cut-off-trees-for-golf-event",
-			"PassRate": "27%",
+			"PassRate": "26%",
 			"Difficulty": "Hard",
 			"IsAccepted": true,
 			"IsPaid": false,
@@ -8137,7 +8137,7 @@
 			"ID": 676,
 			"Title": "Implement Magic Dictionary",
 			"TitleSlug": "implement-magic-dictionary",
-			"PassRate": "49%",
+			"PassRate": "48%",
 			"Difficulty": "Medium",
 			"IsAccepted": true,
 			"IsPaid": false,
@@ -8233,7 +8233,7 @@
 			"ID": 684,
 			"Title": "Redundant Connection",
 			"TitleSlug": "redundant-connection",
-			"PassRate": "43%",
+			"PassRate": "44%",
 			"Difficulty": "Medium",
 			"IsAccepted": true,
 			"IsPaid": false,
@@ -8725,7 +8725,7 @@
 			"ID": 725,
 			"Title": "Split Linked List in Parts",
 			"TitleSlug": "split-linked-list-in-parts",
-			"PassRate": "47%",
+			"PassRate": "46%",
 			"Difficulty": "Medium",
 			"IsAccepted": true,
 			"IsPaid": false,
@@ -9409,7 +9409,7 @@
 			"ID": 782,
 			"Title": "Transform to Chessboard",
 			"TitleSlug": "transform-to-chessboard",
-			"PassRate": "36%",
+			"PassRate": "37%",
 			"Difficulty": "Hard",
 			"IsAccepted": true,
 			"IsPaid": false,
@@ -9493,7 +9493,7 @@
 			"ID": 789,
 			"Title": "Escape The Ghosts",
 			"TitleSlug": "escape-the-ghosts",
-			"PassRate": "49%",
+			"PassRate": "50%",
 			"Difficulty": "Medium",
 			"IsAccepted": true,
 			"IsPaid": false,
@@ -9541,7 +9541,7 @@
 			"ID": 793,
 			"Title": "Preimage Size of Factorial Zeroes Function",
 			"TitleSlug": "preimage-size-of-factorial-zeroes-function",
-			"PassRate": "43%",
+			"PassRate": "42%",
 			"Difficulty": "Hard",
 			"IsAccepted": true,
 			"IsPaid": false,
@@ -9637,7 +9637,7 @@
 			"ID": 801,
 			"Title": "Minimum Swaps To Make Sequences Increasing",
 			"TitleSlug": "minimum-swaps-to-make-sequences-increasing",
-			"PassRate": "26%",
+			"PassRate": "27%",
 			"Difficulty": "Medium",
 			"IsAccepted": true,
 			"IsPaid": false,
@@ -10069,7 +10069,7 @@
 			"ID": 837,
 			"Title": "New 21 Game",
 			"TitleSlug": "new-21-game",
-			"PassRate": "21%",
+			"PassRate": "23%",
 			"Difficulty": "Medium",
 			"IsAccepted": false,
 			"IsPaid": false,
@@ -10081,7 +10081,7 @@
 			"ID": 838,
 			"Title": "Push Dominoes",
 			"TitleSlug": "push-dominoes",
-			"PassRate": "37%",
+			"PassRate": "38%",
 			"Difficulty": "Medium",
 			"IsAccepted": false,
 			"IsPaid": false,