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feat: add solutions to lc problems: No.1370 #2157

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Dec 26, 2023
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feat: add solutions to lc problems: No.1370 #2157

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146 changes: 89 additions & 57 deletions solution/1300-1399/1370.Increasing Decreasing String/README.md
View file
Original file line number Diff line number Diff line change
@@ -73,6 +73,14 @@

<!-- 这里可写通用的实现逻辑 -->

**方法一：计数 + 模拟**

我们先用一个哈希表或者一个长度为 $26$ 的数组 $cnt$ 统计字符串 $s$ 中每个字符出现的次数。

然后，我们枚举字母 $[a,...,z]$，对于当前枚举到的字母 $c$，如果 $cnt[c] \gt 0$，我们就将字母 $c$ 接在答案字符串的末尾，并将 $cnt[c]$ 减一。我们重复这一步骤，直到 $cnt[c]=0$。随后我们逆序枚举字母 $[z,...,a]$，执行类似的操作。如果答案字符串的长度等于 $s$ 的长度，那么我们就完成了所有的拼接操作。

时间复杂度 $O(n \times |\Sigma|)$，空间复杂度 $O(|\Sigma|)$。其中 $n$ 是字符串 $s$ 的长度，而 $\Sigma$ 是字符集，本题中字符集为所有小写字母，因此 $|\Sigma|=26$。

<!-- tabs:start -->

### **Python3**
@@ -82,20 +90,15 @@
```python
class Solution:
def sortString(self, s: str) -> str:
counter = [0] * 26
for c in s:
counter[ord(c) - ord('a')] += 1
cnt = Counter(s)
cs = ascii_lowercase + ascii_lowercase[::-1]
ans = []
while len(ans) < len(s):
for i in range(26):
if counter[i]:
ans.append(chr(i + ord('a')))
counter[i] -= 1
for i in range(25, -1, -1):
if counter[i]:
ans.append(chr(i + ord('a')))
counter[i] -= 1
return ''.join(ans)
for c in cs:
if cnt[c]:
ans.append(c)
cnt[c] -= 1
return "".join(ans)
```

### **Java**
@@ -105,22 +108,23 @@ class Solution:
```java
class Solution {
public String sortString(String s) {
int[] counter = new int[26];
for (char c : s.toCharArray()) {
++counter[c - 'a'];
int[] cnt = new int[26];
int n = s.length();
for (int i = 0; i < n; ++i) {
cnt[s.charAt(i) - 'a']++;
}
StringBuilder sb = new StringBuilder();
while (sb.length() < s.length()) {
while (sb.length() < n) {
for (int i = 0; i < 26; ++i) {
if (counter[i] > 0) {
if (cnt[i] > 0) {
sb.append((char) ('a' + i));
--counter[i];
--cnt[i];
}
}
for (int i = 25; i >= 0; --i) {
if (counter[i] > 0) {
if (cnt[i] > 0) {
sb.append((char) ('a' + i));
--counter[i];
--cnt[i];
}
}
}
@@ -135,20 +139,22 @@ class Solution {
class Solution {
public:
string sortString(string s) {
vector<int> counter(26);
for (char c : s) ++counter[c - 'a'];
string ans = "";
int cnt[26]{};
for (char& c : s) {
++cnt[c - 'a'];
}
string ans;
while (ans.size() < s.size()) {
for (int i = 0; i < 26; ++i) {
if (counter[i]) {
ans += (i + 'a');
--counter[i];
if (cnt[i]) {
ans += i + 'a';
--cnt[i];
}
}
for (int i = 25; i >= 0; --i) {
if (counter[i]) {
ans += (i + 'a');
--counter[i];
if (cnt[i]) {
ans += i + 'a';
--cnt[i];
}
}
}
@@ -161,29 +167,57 @@ public:
```go
func sortString(s string) string {
counter := ['z' + 1]int{}
cnt := [26]int{}
for _, c := range s {
counter[c]++
cnt[c-'a']++
}
var ans []byte
for len(ans) < len(s) {
for i := byte('a'); i <= 'z'; i++ {
if counter[i] > 0 {
ans = append(ans, i)
counter[i]--
n := len(s)
ans := make([]byte, 0, n)
for len(ans) < n {
for i := 0; i < 26; i++ {
if cnt[i] > 0 {
ans = append(ans, byte(i)+'a')
cnt[i]--
}
}
for i := byte('z'); i >= 'a'; i-- {
if counter[i] > 0 {
ans = append(ans, i)
counter[i]--
for i := 25; i >= 0; i-- {
if cnt[i] > 0 {
ans = append(ans, byte(i)+'a')
cnt[i]--
}
}
}
return string(ans)
}
```

### **TypeScript**

```ts
function sortString(s: string): string {
const cnt: number[] = Array(26).fill(0);
for (const c of s) {
++cnt[c.charCodeAt(0) - 'a'.charCodeAt(0)];
}
const ans: string[] = [];
while (ans.length < s.length) {
for (let i = 0; i < 26; ++i) {
if (cnt[i]) {
ans.push(String.fromCharCode(i + 'a'.charCodeAt(0)));
--cnt[i];
}
}
for (let i = 25; i >= 0; --i) {
if (cnt[i]) {
ans.push(String.fromCharCode(i + 'a'.charCodeAt(0)));
--cnt[i];
}
}
}
return ans.join('');
}
```

### **Javascript**

```js
@@ -192,28 +226,26 @@ func sortString(s string) string {
* @return {string}
*/
var sortString = function (s) {
let rs = '';
const m = new Map();
for (let i = 0; i < s.length; i++) {
m.set(s[i], (m.get(s[i]) || 0) + 1);
const cnt = Array(26).fill(0);
for (const c of s) {
++cnt[c.charCodeAt(0) - 'a'.charCodeAt(0)];
}
const keys = [...m.keys()];
keys.sort();
while (rs.length < s.length) {
for (let j = 0; j < keys.length; j++) {
if (m.get(keys[j]) != 0) {
rs += keys[j];
m.set(keys[j], m.get(keys[j]) - 1);
const ans = [];
while (ans.length < s.length) {
for (let i = 0; i < 26; ++i) {
if (cnt[i]) {
ans.push(String.fromCharCode(i + 'a'.charCodeAt(0)));
--cnt[i];
}
}
for (let j = keys.length - 1; j >= 0; j--) {
if (m.get(keys[j]) != 0) {
rs += keys[j];
m.set(keys[j], m.get(keys[j]) - 1);
for (let i = 25; i >= 0; --i) {
if (cnt[i]) {
ans.push(String.fromCharCode(i + 'a'.charCodeAt(0)));
--cnt[i];
}
}
}
return rs;
return ans.join('');
};
```

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