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添加二分Go 代码 #42

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merged 15 commits into from
Jul 29, 2021
Merged

添加二分Go 代码 #42

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7767ea9
Merge pull request #1 from chefyuan/main
lin14543 Jul 17, 2021
40a5eaa
add go for leetcode33
Jul 17, 2021
b46603c
add lc33 in go
Jul 18, 2021
a177043
add 二分查找详解code in Go
Jul 19, 2021
02aaf28
add erfen in go
Jul 20, 2021
e63c35b
add a code in go
Jul 21, 2021
44004ea
add code of 二维数组的二分查找 in go
Jul 22, 2021
5fcc995
add a code in go
Jul 23, 2021
3f2fb19
add lc153 code in go
Jul 24, 2021
a1afdf4
add lc34 code in go
Jul 25, 2021
3096e19
add lc81 code in go
Jul 26, 2021
94d9b4c
Merge branch 'main' into main
lin14543 Jul 26, 2021
d0abf3e
代码重构 【Github Actions】
github-actions[bot] Jul 26, 2021
2072380
Merge branch 'main' into main
chefyuan Jul 29, 2021
0f08417
代码重构 【Github Actions】
github-actions[bot] Jul 29, 2021
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36 changes: 3 additions & 33 deletions animation-simulation/二分查找及其变种/leetcode 81不完全有序查找目标元素(包含重复值) .md
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Original file line number Diff line number Diff line change
Expand Up @@ -40,10 +40,12 @@

#### **题目代码**

Java Code:

```java
class Solution {
public boolean search(int[] nums, int target) {
int left = 0;
int left = 0;
int right = nums.length - 1;
while (left <= right) {
int mid = left+((right-left)>>1);
Expand Down Expand Up @@ -73,35 +75,3 @@ class Solution {
}
}
```

Go Code:

```go
func search(nums []int, target int) bool {
l, r := 0, len(nums) - 1
for l <= r {
m := l + (r - l) / 2
if nums[m] == target {
return true
}
// 先判断哪边是递增的，再查找范围
if nums[m] == nums[l] {
l++
} else if nums[l] < nums[m] {
// 判断target是否在有序的那边就行了。
if nums[l] <= target && target < nums[m] {
r = m - 1
} else {
l = m + 1
}
} else if nums[l] > nums[m] {
if nums[m] < target && target <= nums[r] {
l = m + 1
} else {
r = m - 1
}
}
}
return false
}
```
20 changes: 0 additions & 20 deletions animation-simulation/二分查找及其变种/leetcode153搜索旋转数组的最小值.md
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Original file line number Diff line number Diff line change
Expand Up @@ -104,23 +104,3 @@ public:
}
};
```

Go Code:

```go
func findMin(nums []int) int {
l, r := 0, len(nums) - 1
for l < r {
if nums[l] < nums[r] {
return nums[l]
}
m := l + (r - l) / 2
if nums[l] > nums[m] {
r = m
} else {
l = m + 1
}
}
return nums[l]
}
```
34 changes: 2 additions & 32 deletions animation-simulation/二分查找及其变种/leetcode33不完全有序查找目标元素(不包含重复值).md
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Original file line number Diff line number Diff line change
Expand Up @@ -89,6 +89,8 @@

#### 题目代码

Java Code:

```java
class Solution {
public int search(int[] nums, int target) {
Expand Down Expand Up @@ -126,35 +128,3 @@ class Solution {
}
}
```

Go Code:

```go
func search(nums []int, target int) int {
l, r := 0, len(nums) - 1
for l <= r {
m := (l + r) / 2
if target == nums[m] {
return m
}
// 先判断哪边是有序的
if nums[m] < nums[r] {
// 再判断target在左右哪边
if target > nums[m] && target <= nums[r] {
l = m + 1
} else {
r = m - 1
}
} else {
if target < nums[m] && target >= nums[l] {
r = m - 1
} else {
l = m + 1
}
}
}
return -1
}
```

##
44 changes: 2 additions & 42 deletions animation-simulation/二分查找及其变种/leetcode34查找第一个位置和最后一个位置.md
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Original file line number Diff line number Diff line change
Expand Up @@ -122,6 +122,8 @@ int upperBound(int[] nums, int target) {

#### **题目完整代码**

Java Code:

```java
class Solution {
public int[] searchRange (int[] nums, int target) {
Expand Down Expand Up @@ -166,45 +168,3 @@ class Solution {
}
}
```

Go Code:

```go
func searchRange(nums []int, target int) []int {
upper := upperBound(nums, target)
lower := lowerBound(nums, target)

if (upper < lower) {
return []int{-1, -1}
}
return []int{lower, upper}
}

// upperBound 计算上边界
func upperBound(nums []int, target int) int {
l, r := 0, len(nums) - 1
for l <= r {
m := l + (r - l) / 2
if target >= nums[m] {
l = m + 1
} else if target < nums[m] {
r = m - 1
}
}
return r
}

// lowerBound 计算下边界
func lowerBound(nums []int, target int) int {
l, r := 0, len(nums) - 1
for l <= r {
m := l + (r - l) / 2
if target <= nums[m] {
r = m - 1
} else if target > nums[m] {
l = m + 1
}
}
return l
}
```
20 changes: 2 additions & 18 deletions animation-simulation/二分查找及其变种/leetcode35搜索插入位置.md
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Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,8 @@

#### 题目代码

Java Code:

```java
class Solution {
public int searchInsert(int[] nums, int target) {
Expand Down Expand Up @@ -67,21 +69,3 @@ class Solution {
```

Go Code:

```go
func searchInsert(nums []int, target int) int {
l, r := 0, len(nums) - 1
for l <= r {
m := l + (r - l) / 2
if target == nums[m] {
return m
}
if target < nums[m] {
r = m - 1
} else if target > nums[m] {
l = m + 1
}
}
return l
}
```
110 changes: 80 additions & 30 deletions animation-simulation/二分查找及其变种/二分查找详解.md
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Original file line number Diff line number Diff line change
Expand Up @@ -94,25 +94,50 @@ target < nums[mid] 则在左半区间继续进行搜索，即 right = mid -1；

下面我们来看一下二分查找的代码，可以认真思考一下 if 语句的条件，每个都没有简写。

Java Code:

```java
public static int binarySearch(int[] nums,int target,int left, int right) {
//这里需要注意，循环条件
while (left <= right) {
//这里需要注意，计算mid
int mid = left + ((right - left) >> 1);
if (nums[mid] == target) {
return mid;
}else if (nums[mid] < target) {
//这里需要注意，移动左指针
left = mid + 1;
}else if (nums[mid] > target) {
//这里需要注意，移动右指针
right = mid - 1;
}
public static int binarySearch(int[] nums,int target,int left, int right) {
//这里需要注意，循环条件
while (left <= right) {
//这里需要注意，计算mid
int mid = left + ((right - left) >> 1);
if (nums[mid] == target) {
return mid;
}else if (nums[mid] < target) {
//这里需要注意，移动左指针
left = mid + 1;
}else if (nums[mid] > target) {
//这里需要注意，移动右指针
right = mid - 1;
}
//没有找到该元素，返回 -1
return -1;
}
//没有找到该元素，返回 -1
return -1;
}
```

Go Code:

```go
func binarySearch(nums []int, target, left, right int) int {
//这里需要注意，循环条件
for left <= right {
//这里需要注意，计算mid
mid := left + ((right - left) >> 1)
if nums[mid] == target {
return mid
} else if nums[mid] < target {
//这里需要注意，移动左指针
left = mid + 1
} else if nums[mid] > target {
//这里需要注意，移动右指针
right = mid - 1
}
}
//没有找到该元素，返回 -1
return -1
}
```

二分查找的思路及代码已经理解了，那么我们来看一下实现时容易出错的地方
Expand All @@ -127,23 +152,48 @@ target < nums[mid] 则在左半区间继续进行搜索，即 right = mid -1；

下面我们来看一下二分查找的递归写法

Java Code:

```java
public static int binarySearch(int[] nums,int target,int left, int right) {

if (left <= right) {
int mid = left + ((right - left) >> 1);
if (nums[mid] == target) {
//查找成功
return mid;
}else if (nums[mid] > target) {
//新的区间,左半区间
return binarySearch(nums,target,left,mid-1);
}else if (nums[mid] < target) {
//新的区间，右半区间
return binarySearch(nums,target,mid+1,right);
}
if (left <= right) {
int mid = left + ((right - left) >> 1);
if (nums[mid] == target) {
//查找成功
return mid;
}else if (nums[mid] > target) {
//新的区间,左半区间
return binarySearch(nums,target,left,mid-1);
}else if (nums[mid] < target) {
//新的区间，右半区间
return binarySearch(nums,target,mid+1,right);
}
//不存在返回-1
return -1;
}
//不存在返回-1
return -1;
}
```

Go Code:

```go
func binarySearch(nums []int, target, left, right int) int {

if left <= right {
mid := left + ((right - left) >> 1)
if nums[mid] == target {
//查找成功
return mid
} else if nums[mid] > target {
//新的区间,左半区间
return binarySearch(nums, target, left, mid-1)
} else if nums[mid] < target {
//新的区间，右半区间
return binarySearch(nums, target, mid+1, right)
}
}
//不存在返回-1
return -1
}
```
29 changes: 2 additions & 27 deletions animation-simulation/二分查找及其变种/二维数组的二分查找.md
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Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,8 @@

#### 题目代码

Java Code:

```java
class Solution {
public boolean searchMatrix(int[][] matrix, int target) {
Expand Down Expand Up @@ -83,30 +85,3 @@ class Solution {
}
}
```

Go Code:

```go
func searchMatrix(matrix [][]int, target int) bool {
if len(matrix) == 0 {
return false
}
row, col := len(matrix), len(matrix[0])
// 将二维数组拉平为一维。
l, r := 0, row * col - 1
for l <= r {
m := l + (r - l) / 2
// 将一维的坐标转换为二维
x, y := m / col, m % col
if matrix[x][y] == target {
return true
} else if matrix[x][y] < target {
l = m + 1
} else if matrix[x][y] > target {
// 二分查找时，把所有的情况都要写出来，避免直接else
r = m - 1
}
}
return false
}
```
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