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feat: update solutions to lcci problem: No.01.02 

No.01.02.Check Permutation
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yanglbme 2022-09-27 09:03:57 +08:00
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commit d44534b0ba
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177
lcci/01.02.Check Permutation/README.md
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@ -30,15 +30,25 @@
<!-- 这里可写通用的实现逻辑 -->
**方法一：哈希表**
**方法一：数组或哈希表**
使用哈希表作为字符计数器。
先判断两个字符串的长度是否相等，若不相等则直接返回 `false`。
时间复杂度 $O(n)$。
然后用一个数组或哈希表统计字符串 $s1$ 中字符出现的次数。
接着遍历另一个字符串 $s2$，每遍历到一个字符，就将该字符对应的次数减一，如果减一后的次数小于 $0$，则说明两个字符串中字符出现的次数不同，直接返回 `false`。
最后遍历完字符串 $s2$，返回 `true`。
注意：本题测试用例所有字符串仅包含小写字母，因此我们可以直接开一个长度为 $26$ 的数组来计数。
时间复杂度 $O(n)$，空间复杂度 $O(C)$。其中 $n$ 为字符串的长度，而 $C$ 为字符集的大小，本题 $C=26$。
**方法二：排序**
按照字符编码重新排序字符串，再检查两者一致性。
按照字典序对两个字符串进行排序，然后比较两个字符串是否相等。
时间复杂度 $O(n\log n)$，空间复杂度 $O(1)$。
<!-- tabs:start -->
@ -49,14 +59,13 @@
```python
class Solution:
def CheckPermutation(self, s1: str, s2: str) -> bool:
n1, n2 = len(s1), len(s2)
if n1 != n2:
return False
counter = Counter()
for i in range(n1):
counter[s1[i]] += 1
counter[s2[i]] -= 1
return all(v == 0 for v in counter.values())
return Counter(s1) == Counter(s2)
```
```python
class Solution:
def CheckPermutation(self, s1: str, s2: str) -> bool:
return sorted(s1) == sorted(s2)
```
### **Java**
@ -66,18 +75,15 @@ class Solution:
```java
class Solution {
public boolean CheckPermutation(String s1, String s2) {
int n1 = s1.length();
int n2 = s2.length();
if (n1 != n2) {
if (s1.length() != s2.length()) {
return false;
}
int[] counter = new int[128];
for (int i = 0; i < n1; ++i) {
++counter[s1.charAt(i)];
--counter[s2.charAt(i)];
int[] cnt = new int[26];
for (char c : s1.toCharArray()) {
++cnt[c - 'a'];
}
for (int v : counter) {
if (v != 0) {
for (char c : s2.toCharArray()) {
if (--cnt[c - 'a'] < 0) {
return false;
}
}
@ -86,44 +92,15 @@ class Solution {
}
```
### **JavaScript**
```js
var CheckPermutation = function (s1, s2) {
let n1 = s1.length,
n2 = s2.length;
if (n1 != n2) return false;
let counter = {};
for (let i = 0; i < n1; i++) {
let cur1 = s1.charAt(i),
cur2 = s2.charAt(i);
counter[cur1] = (counter[cur1] || 0) + 1;
counter[cur2] = (counter[cur2] || 0) - 1;
```java
class Solution {
public boolean CheckPermutation(String s1, String s2) {
char[] cs1 = s1.toCharArray();
char[] cs2 = s2.toCharArray();
Arrays.sort(cs1);
Arrays.sort(cs2);
return Arrays.equals(cs1, cs2);
}
return Object.values(counter).every(v => v == 0);
};
```
### **Go**
```go
func CheckPermutation(s1 string, s2 string) bool {
freq := make(map[rune]int)
for _, r := range s1 {
freq[r]++
}
for _, r := range s2 {
if freq[r] == 0 {
return false
}
freq[r]--
}
for _, v := range freq {
if v != 0 {
return false
}
}
return true
}
```
@ -133,21 +110,83 @@ func CheckPermutation(s1 string, s2 string) bool {
class Solution {
public:
bool CheckPermutation(string s1, string s2) {
int n1 = s1.size();
int n2 = s2.size();
if (n1 != n2) return 0;
vector<int> counter(128);
for (int i = 0; i < n1; ++i) {
++counter[s1[i]];
--counter[s2[i]];
}
for (int v : counter)
if (v) return 0;
return 1;
if (s1.size() != s2.size()) return false;
int cnt[26] = {0};
for (char & c : s1) ++cnt[c - 'a'];
for (char & c : s2) if (--cnt[c - 'a'] < 0) return false;
return true;
}
};
```
```cpp
class Solution {
public:
bool CheckPermutation(string s1, string s2) {
sort(s1.begin(), s1.end());
sort(s2.begin(), s2.end());
return s1 == s2;
}
};
```
### **Go**
```go
func CheckPermutation(s1 string, s2 string) bool {
if len(s1) != len(s2) {
return false
}
cnt := make([]int, 26)
for _, c := range s1 {
cnt[c-'a']++
}
for _, c := range s2 {
cnt[c-'a']--
if cnt[c-'a'] < 0 {
return false
}
}
return true
}
```
```go
func CheckPermutation(s1 string, s2 string) bool {
cs1, cs2 := []byte(s1), []byte(s2)
sort.Slice(cs1, func(i, j int) bool { return cs1[i] < cs1[j] })
sort.Slice(cs2, func(i, j int) bool { return cs2[i] < cs2[j] })
return string(cs1) == string(cs2)
}
```
### **JavaScript**
```js
/**
* @param {string} s1
* @param {string} s2
* @return {boolean}
*/
var CheckPermutation = function(s1, s2) {
if (s1.length != s2.length) {
return false;
}
const cnt = new Array(26).fill(0);
for (let i = 0; i < s1.length; ++i) {
const j = s1.codePointAt(i) - 'a'.codePointAt(0);
++cnt[j];
}
for (let i = 0; i < s2.length; ++i) {
const j = s2.codePointAt(i) - 'a'.codePointAt(0);
if (--cnt[j] < 0) {
return false;
}
}
return true;
};
```
### **TypeScript**
```ts

159
lcci/01.02.Check Permutation/README_EN.md
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@ -41,14 +41,13 @@
```python
class Solution:
def CheckPermutation(self, s1: str, s2: str) -> bool:
n1, n2 = len(s1), len(s2)
if n1 != n2:
return False
counter = Counter()
for i in range(n1):
counter[s1[i]] += 1
counter[s2[i]] -= 1
return all(v == 0 for v in counter.values())
return Counter(s1) == Counter(s2)
```
```python
class Solution:
def CheckPermutation(self, s1: str, s2: str) -> bool:
return sorted(s1) == sorted(s2)
```
### **Java**
@ -56,18 +55,15 @@ class Solution:
```java
class Solution {
public boolean CheckPermutation(String s1, String s2) {
int n1 = s1.length();
int n2 = s2.length();
if (n1 != n2) {
if (s1.length() != s2.length()) {
return false;
}
int[] counter = new int[128];
for (int i = 0; i < n1; ++i) {
++counter[s1.charAt(i)];
--counter[s2.charAt(i)];
int[] cnt = new int[26];
for (char c : s1.toCharArray()) {
++cnt[c - 'a'];
}
for (int v : counter) {
if (v != 0) {
for (char c : s2.toCharArray()) {
if (--cnt[c - 'a'] < 0) {
return false;
}
}
@ -76,44 +72,15 @@ class Solution {
}
```
### **JavaScript**
```js
var CheckPermutation = function (s1, s2) {
let n1 = s1.length,
n2 = s2.length;
if (n1 != n2) return false;
let counter = {};
for (let i = 0; i < n1; i++) {
let cur1 = s1.charAt(i),
cur2 = s2.charAt(i);
counter[cur1] = (counter[cur1] || 0) + 1;
counter[cur2] = (counter[cur2] || 0) - 1;
```java
class Solution {
public boolean CheckPermutation(String s1, String s2) {
char[] cs1 = s1.toCharArray();
char[] cs2 = s2.toCharArray();
Arrays.sort(cs1);
Arrays.sort(cs2);
return Arrays.equals(cs1, cs2);
}
return Object.values(counter).every(v => v == 0);
};
```
### **Go**
```go
func CheckPermutation(s1 string, s2 string) bool {
freq := make(map[rune]int)
for _, r := range s1 {
freq[r]++
}
for _, r := range s2 {
if freq[r] == 0 {
return false
}
freq[r]--
}
for _, v := range freq {
if v != 0 {
return false
}
}
return true
}
```
@ -123,21 +90,83 @@ func CheckPermutation(s1 string, s2 string) bool {
class Solution {
public:
bool CheckPermutation(string s1, string s2) {
int n1 = s1.size();
int n2 = s2.size();
if (n1 != n2) return 0;
vector<int> counter(128);
for (int i = 0; i < n1; ++i) {
++counter[s1[i]];
--counter[s2[i]];
}
for (int v : counter)
if (v) return 0;
return 1;
if (s1.size() != s2.size()) return false;
int cnt[26] = {0};
for (char & c : s1) ++cnt[c - 'a'];
for (char & c : s2) if (--cnt[c - 'a'] < 0) return false;
return true;
}
};
```
```cpp
class Solution {
public:
bool CheckPermutation(string s1, string s2) {
sort(s1.begin(), s1.end());
sort(s2.begin(), s2.end());
return s1 == s2;
}
};
```
### **Go**
```go
func CheckPermutation(s1 string, s2 string) bool {
if len(s1) != len(s2) {
return false
}
cnt := make([]int, 26)
for _, c := range s1 {
cnt[c-'a']++
}
for _, c := range s2 {
cnt[c-'a']--
if cnt[c-'a'] < 0 {
return false
}
}
return true
}
```
```go
func CheckPermutation(s1 string, s2 string) bool {
cs1, cs2 := []byte(s1), []byte(s2)
sort.Slice(cs1, func(i, j int) bool { return cs1[i] < cs1[j] })
sort.Slice(cs2, func(i, j int) bool { return cs2[i] < cs2[j] })
return string(cs1) == string(cs2)
}
```
### **JavaScript**
```js
/**
* @param {string} s1
* @param {string} s2
* @return {boolean}
*/
var CheckPermutation = function(s1, s2) {
if (s1.length != s2.length) {
return false;
}
const cnt = new Array(26).fill(0);
for (let i = 0; i < s1.length; ++i) {
const j = s1.codePointAt(i) - 'a'.codePointAt(0);
++cnt[j];
}
for (let i = 0; i < s2.length; ++i) {
const j = s2.codePointAt(i) - 'a'.codePointAt(0);
if (--cnt[j] < 0) {
return false;
}
}
return true;
};
```
### **TypeScript**
```ts

16
lcci/01.02.Check Permutation/Solution.cpp
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@ -1,16 +1,10 @@
class Solution {
public:
bool CheckPermutation(string s1, string s2) {
int n1 = s1.size();
int n2 = s2.size();
if (n1 != n2) return 0;
vector<int> counter(128);
for (int i = 0; i < n1; ++i) {
++counter[s1[i]];
--counter[s2[i]];
}
for (int v : counter)
if (v) return 0;
return 1;
if (s1.size() != s2.size()) return false;
int cnt[26] = {0};
for (char & c : s1) ++cnt[c - 'a'];
for (char & c : s2) if (--cnt[c - 'a'] < 0) return false;
return true;
}
};

20
lcci/01.02.Check Permutation/Solution.go
View File

@ -1,18 +1,16 @@
func CheckPermutation(s1 string, s2 string) bool {
freq := make(map[rune]int)
for _, r := range s1 {
freq[r]++
if len(s1) != len(s2) {
return false
}
for _, r := range s2 {
if freq[r] == 0 {
return false
}
freq[r]--
cnt := make([]int, 26)
for _, c := range s1 {
cnt[c-'a']++
}
for _, v := range freq {
if v != 0 {
for _, c := range s2 {
cnt[c-'a']--
if cnt[c-'a'] < 0 {
return false
}
}
return true
}
}

16
lcci/01.02.Check Permutation/Solution.java
View File

@ -1,17 +1,11 @@
class Solution {
public boolean CheckPermutation(String s1, String s2) {
int n1 = s1.length();
int n2 = s2.length();
if (n1 != n2) {
return false;
int[] cnt = new int[26];
for (char c : s1.toCharArray()) {
++cnt[c - 'a'];
}
int[] counter = new int[128];
for (int i = 0; i < n1; ++i) {
++counter[s1.charAt(i)];
--counter[s2.charAt(i)];
}
for (int v : counter) {
if (v != 0) {
for (char c : s2.toCharArray()) {
if (--cnt[c - 'a'] < 0) {
return false;
}
}

24
lcci/01.02.Check Permutation/Solution.js
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@ -4,15 +4,19 @@
* @return {boolean}
*/
var CheckPermutation = function (s1, s2) {
let n1 = s1.length,
n2 = s2.length;
if (n1 != n2) return false;
let counter = {};
for (let i = 0; i < n1; i++) {
let cur1 = s1.charAt(i),
cur2 = s2.charAt(i);
counter[cur1] = (counter[cur1] || 0) + 1;
counter[cur2] = (counter[cur2] || 0) - 1;
if (s1.length != s2.length) {
return false;
}
return Object.values(counter).every(v => v == 0);
const cnt = new Array(26).fill(0);
for (let i = 0; i < s1.length; ++i) {
const j = s1.codePointAt(i) - 'a'.codePointAt(0);
++cnt[j];
}
for (let i = 0; i < s2.length; ++i) {
const j = s2.codePointAt(i) - 'a'.codePointAt(0);
if (--cnt[j] < 0) {
return false;
}
}
return true;
};

9
lcci/01.02.Check Permutation/Solution.py
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@ -1,10 +1,3 @@
class Solution:
def CheckPermutation(self, s1: str, s2: str) -> bool:
n1, n2 = len(s1), len(s2)
if n1 != n2:
return False
counter = Counter()
for i in range(n1):
counter[s1[i]] += 1
counter[s2[i]] -= 1
return all(v == 0 for v in counter.values())
return Counter(s1) == Counter(s2)