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Merge pull request #711 from nolanzzz/master

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添加 链表+哈希表类题目9道 PHP版本
This commit is contained in:
程序员Carl
2021-09-04 17:03:26 +08:00
committed by GitHub
parent 345b66bd43 e8151aa146
commit e85680274c
9 changed files with 290 additions and 2 deletions
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25
problems/0001.两数之和.md
View File

@ -224,6 +224,31 @@ func twoSum(_ nums: [Int], _ target: Int) -> [Int] {
}
```
PHP:
```php
class Solution {
/**
* @param Integer[] $nums
* @param Integer $target
* @return Integer[]
*/
function twoSum($nums, $target) {
if (count($nums) == 0) {
return [];
}
$table = [];
for ($i = 0; $i < count($nums); $i++) {
$temp = $target - $nums[$i];
if (isset($table[$temp])) {
return [$table[$temp], $i];
}
$table[$nums[$i]] = $i;
}
return [];
}
}
```
-----------------------
* 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw)
* B站视频：[代码随想录](https://space.bilibili.com/525438321)

40
problems/0015.三数之和.md
View File

@ -393,6 +393,46 @@ function threeSum(array $nums): array
}
```
PHP:
```php
class Solution {
/**
* @param Integer[] $nums
* @return Integer[][]
*/
function threeSum($nums) {
$res = [];
sort($nums);
for ($i = 0; $i < count($nums); $i++) {
if ($nums[$i] > 0) {
return $res;
}
if ($i > 0 && $nums[$i] == $nums[$i - 1]) {
continue;
}
$left = $i + 1;
$right = count($nums) - 1;
while ($left < $right) {
$sum = $nums[$i] + $nums[$left] + $nums[$right];
if ($sum < 0) {
$left++;
}
else if ($sum > 0) {
$right--;
}
else {
$res[] = [$nums[$i], $nums[$left], $nums[$right]];
while ($left < $right && $nums[$left] == $nums[$left + 1]) $left++;
while ($left < $right && $nums[$right] == $nums[$right - 1]) $right--;
$left++;
$right--;
}
}
}
return $res;
}
}
```
-----------------------

43
problems/0018.四数之和.md
View File

@ -310,6 +310,49 @@ var fourSum = function(nums, target) {
};
```
PHP:
```php
class Solution {
/**
* @param Integer[] $nums
* @param Integer $target
* @return Integer[][]
*/
function fourSum($nums, $target) {
$res = [];
sort($nums);
for ($i = 0; $i < count($nums); $i++) {
if ($i > 0 && $nums[$i] == $nums[$i - 1]) {
continue;
}
for ($j = $i + 1; $j < count($nums); $j++) {
if ($j > $i + 1 && $nums[$j] == $nums[$j - 1]) {
continue;
}
$left = $j + 1;
$right = count($nums) - 1;
while ($left < $right) {
$sum = $nums[$i] + $nums[$j] + $nums[$left] + $nums[$right];
if ($sum < $target) {
$left++;
}
else if ($sum > $target) {
$right--;
}
else {
$res[] = [$nums[$i], $nums[$j], $nums[$left], $nums[$right]];
while ($left < $right && $nums[$left] == $nums[$left+1]) $left++;
while ($left < $right && $nums[$right] == $nums[$right-1]) $right--;
$left++;
$right--;
}
}
}
}
return $res;
}
}
```
-----------------------
* 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw)

31
problems/0202.快乐数.md
View File

@ -223,6 +223,37 @@ func isHappy(_ n: Int) -> Bool {
}
```
PHP:
```php
class Solution {
/**
* @param Integer $n
* @return Boolean
*/
function isHappy($n) {
// use a set to record sum
// whenever there is a duplicated, stop
// == 1 return true, else false
$table = [];
while ($n != 1 && !isset($table[$n])) {
$table[$n] = 1;
$n = self::getNextN($n);
}
return $n == 1;
}
function getNextN(int $n) {
$res = 0;
while ($n > 0) {
$temp = $n % 10;
$res += $temp * $temp;
$n = floor($n / 10);
}
return $res;
}
}
```
-----------------------
* 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw)
* B站视频：[代码随想录](https://space.bilibili.com/525438321)

28
problems/0203.移除链表元素.md
View File

@ -331,8 +331,32 @@ func removeElements(_ head: ListNode?, _ val: Int) -> ListNode? {
}
```
PHP:
```php
/**
* Definition for singly-linked list.
* type ListNode struct {
* Val int
* Next *ListNode
* }
*/
// 虚拟头+双指针
func removeElements(head *ListNode, val int) *ListNode {
dummyHead := &ListNode{}
dummyHead.Next = head
pred := dummyHead
cur := head
for cur != nil {
if cur.Val == val {
pred.Next = cur.Next
} else {
pred = cur
}
cur = cur.Next
}
return dummyHead.Next
}
```
-----------------------
* 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw)

35
problems/0242.有效的字母异位词.md
View File

@ -221,6 +221,41 @@ func isAnagram(_ s: String, _ t: String) -> Bool {
}
```
PHP：
```php
class Solution {
/**
* @param String $s
* @param String $t
* @return Boolean
*/
function isAnagram($s, $t) {
if (strlen($s) != strlen($t)) {
return false;
}
$table = [];
for ($i = 0; $i < strlen($s); $i++) {
if (!isset($table[$s[$i]])) {
$table[$s[$i]] = 1;
} else {
$table[$s[$i]]++;
}
if (!isset($table[$t[$i]])) {
$table[$t[$i]] = -1;
} else {
$table[$t[$i]]--;
}
}
foreach ($table as $record) {
if ($record != 0) {
return false;
}
}
return true;
}
}
```
## 相关题目
* 383.赎金信

29
problems/0349.两个数组的交集.md
View File

@ -209,6 +209,35 @@ func intersection(_ nums1: [Int], _ nums2: [Int]) -> [Int] {
}
```
PHP:
```php
class Solution {
/**
* @param Integer[] $nums1
* @param Integer[] $nums2
* @return Integer[]
*/
function intersection($nums1, $nums2) {
if (count($nums1) == 0 || count($nums2) == 0) {
return [];
}
$counts = [];
$res = [];
foreach ($nums1 as $num) {
$counts[$num] = 1;
}
foreach ($nums2 as $num) {
if (isset($counts[$num])) {
$res[] = $num;
}
unset($counts[$num]);
}
return $res;
}
}
```
## 相关题目
* 350.两个数组的交集 II

26
problems/0383.赎金信.md
View File

@ -266,6 +266,32 @@ var canConstruct = function(ransomNote, magazine) {
};
```
PHP:
```php
class Solution {
/**
* @param String $ransomNote
* @param String $magazine
* @return Boolean
*/
function canConstruct($ransomNote, $magazine) {
if (count($ransomNote) > count($magazine)) {
return false;
}
$map = [];
for ($i = 0; $i < strlen($magazine); $i++) {
$map[$magazine[$i]] = ($map[$magazine[$i]] ?? 0) + 1;
}
for ($i = 0; $i < strlen($ransomNote); $i++) {
if (!isset($map[$ransomNote[$i]]) || --$map[$ransomNote[$i]] < 0) {
return false;
}
}
return true;
}
```
Swift：
```swift
func canConstruct(_ ransomNote: String, _ magazine: String) -> Bool {

35
problems/0454.四数相加II.md
View File

@ -220,6 +220,40 @@ var fourSumCount = function(nums1, nums2, nums3, nums4) {
};
```
PHP:
```php
class Solution {
/**
* @param Integer[] $nums1
* @param Integer[] $nums2
* @param Integer[] $nums3
* @param Integer[] $nums4
* @return Integer
*/
function fourSumCount($nums1, $nums2, $nums3, $nums4) {
$map = [];
foreach ($nums1 as $n1) {
foreach ($nums2 as $n2) {
$temp = $n1 + $n2;
$map[$temp] = isset($map[$temp]) ? $map[$temp]+1 : 1;
}
}
$count = 0;
foreach ($nums3 as $n3) {
foreach ($nums4 as $n4) {
$temp = 0 - $n3 - $n4;
if (isset($map[$temp])) {
$count += $map[$temp];
}
}
}
return $count;
}
}
```
Swift：
```swift
func fourSumCount(_ nums1: [Int], _ nums2: [Int], _ nums3: [Int], _ nums4: [Int]) -> Int {
@ -248,6 +282,7 @@ func fourSumCount(_ nums1: [Int], _ nums2: [Int], _ nums3: [Int], _ nums4: [Int]
}
```
-----------------------
* 作者微信：[程序员Carl](https://mp.weixin.qq.com/s/b66DFkOp8OOxdZC_xLZxfw)
* B站视频：[代码随想录](https://space.bilibili.com/525438321)