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feat: add solutions to lc problems: No.3042,3045 #2350

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Feb 18, 2024
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feat: add solutions to lc problems: No.3042,3045 #2350

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175 changes: 175 additions & 0 deletions solution/3000-3099/3042.Count Prefix and Suffix Pairs I/README.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -67,19 +67,194 @@ i = 2 且 j = 3 ，因为 isPrefixAndSuffix("ma", "mama") 为 true 。
<!-- tabs:start -->

```python
class Solution:
def countPrefixSuffixPairs(self, words: List[str]) -> int:
ans = 0
for i, s in enumerate(words):
for t in words[i + 1 :]:
ans += t.endswith(s) and t.startswith(s)
return ans
```

```java
class Solution {
public int countPrefixSuffixPairs(String[] words) {
int ans = 0;
int n = words.length;
for (int i = 0; i < n; ++i) {
String s = words[i];
for (int j = i + 1; j < n; ++j) {
String t = words[j];
if (t.startsWith(s) && t.endsWith(s)) {
++ans;
}
}
}
return ans;
}
}
```

```cpp
class Solution {
public:
int countPrefixSuffixPairs(vector<string>& words) {
int ans = 0;
int n = words.size();
for (int i = 0; i < n; ++i) {
string s = words[i];
for (int j = i + 1; j < n; ++j) {
string t = words[j];
if (t.find(s) == 0 && t.rfind(s) == t.length() - s.length()) {
++ans;
}
}
}
return ans;
}
};
```

```go
func countPrefixSuffixPairs(words []string) (ans int) {
for i, s := range words {
for _, t := range words[i+1:] {
if strings.HasPrefix(t, s) && strings.HasSuffix(t, s) {
ans++
}
}
}
return
}
```

```ts
function countPrefixSuffixPairs(words: string[]): number {
let ans = 0;
for (let i = 0; i < words.length; ++i) {
const s = words[i];
for (const t of words.slice(i + 1)) {
if (t.startsWith(s) && t.endsWith(s)) {
++ans;
}
}
}
return ans;
}
```

<!-- tabs:end -->

### 方法二

<!-- tabs:start -->

```python
class Node:
__slots__ = ["children", "cnt"]

def __init__(self):
self.children = {}
self.cnt = 0


class Solution:
def countPrefixSuffixPairs(self, words: List[str]) -> int:
ans = 0
trie = Node()
for s in words:
node = trie
for p in zip(s, reversed(s)):
if p not in node.children:
node.children[p] = Node()
node = node.children[p]
ans += node.cnt
node.cnt += 1
return ans
```

```java
class Node {
Map<Integer, Node> children = new HashMap<>();
int cnt;
}

class Solution {
public int countPrefixSuffixPairs(String[] words) {
int ans = 0;
Node trie = new Node();
for (String s : words) {
Node node = trie;
int m = s.length();
for (int i = 0; i < m; ++i) {
int p = s.charAt(i) * 32 + s.charAt(m - i - 1);
node.children.putIfAbsent(p, new Node());
node = node.children.get(p);
ans += node.cnt;
}
++node.cnt;
}
return ans;
}
}
```

```cpp
class Node {
public:
unordered_map<int, Node*> children;
int cnt;

Node()
: cnt(0) {}
};

class Solution {
public:
int countPrefixSuffixPairs(vector<string>& words) {
int ans = 0;
Node* trie = new Node();
for (const string& s : words) {
Node* node = trie;
int m = s.length();
for (int i = 0; i < m; ++i) {
int p = s[i] * 32 + s[m - i - 1];
if (node->children.find(p) == node->children.end()) {
node->children[p] = new Node();
}
node = node->children[p];
ans += node->cnt;
}
++node->cnt;
}
return ans;
}
};
```

```go
type Node struct {
children map[int]*Node
cnt int
}

func countPrefixSuffixPairs(words []string) (ans int) {
trie := &Node{children: make(map[int]*Node)}
for _, s := range words {
node := trie
m := len(s)
for i := 0; i < m; i++ {
p := int(s[i])*32 + int(s[m-i-1])
if _, ok := node.children[p]; !ok {
node.children[p] = &Node{children: make(map[int]*Node)}
}
node = node.children[p]
ans += node.cnt
}
node.cnt++
}
return
}
```

<!-- tabs:end -->
Expand Down
175 changes: 175 additions & 0 deletions solution/3000-3099/3042.Count Prefix and Suffix Pairs I/README_EN.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -63,19 +63,194 @@ Therefore, the answer is 0.</pre>
<!-- tabs:start -->

```python
class Solution:
def countPrefixSuffixPairs(self, words: List[str]) -> int:
ans = 0
for i, s in enumerate(words):
for t in words[i + 1 :]:
ans += t.endswith(s) and t.startswith(s)
return ans
```

```java
class Solution {
public int countPrefixSuffixPairs(String[] words) {
int ans = 0;
int n = words.length;
for (int i = 0; i < n; ++i) {
String s = words[i];
for (int j = i + 1; j < n; ++j) {
String t = words[j];
if (t.startsWith(s) && t.endsWith(s)) {
++ans;
}
}
}
return ans;
}
}
```

```cpp
class Solution {
public:
int countPrefixSuffixPairs(vector<string>& words) {
int ans = 0;
int n = words.size();
for (int i = 0; i < n; ++i) {
string s = words[i];
for (int j = i + 1; j < n; ++j) {
string t = words[j];
if (t.find(s) == 0 && t.rfind(s) == t.length() - s.length()) {
++ans;
}
}
}
return ans;
}
};
```

```go
func countPrefixSuffixPairs(words []string) (ans int) {
for i, s := range words {
for _, t := range words[i+1:] {
if strings.HasPrefix(t, s) && strings.HasSuffix(t, s) {
ans++
}
}
}
return
}
```

```ts
function countPrefixSuffixPairs(words: string[]): number {
let ans = 0;
for (let i = 0; i < words.length; ++i) {
const s = words[i];
for (const t of words.slice(i + 1)) {
if (t.startsWith(s) && t.endsWith(s)) {
++ans;
}
}
}
return ans;
}
```

<!-- tabs:end -->

### Solution 2

<!-- tabs:start -->

```python
class Node:
__slots__ = ["children", "cnt"]

def __init__(self):
self.children = {}
self.cnt = 0


class Solution:
def countPrefixSuffixPairs(self, words: List[str]) -> int:
ans = 0
trie = Node()
for s in words:
node = trie
for p in zip(s, reversed(s)):
if p not in node.children:
node.children[p] = Node()
node = node.children[p]
ans += node.cnt
node.cnt += 1
return ans
```

```java
class Node {
Map<Integer, Node> children = new HashMap<>();
int cnt;
}

class Solution {
public int countPrefixSuffixPairs(String[] words) {
int ans = 0;
Node trie = new Node();
for (String s : words) {
Node node = trie;
int m = s.length();
for (int i = 0; i < m; ++i) {
int p = s.charAt(i) * 32 + s.charAt(m - i - 1);
node.children.putIfAbsent(p, new Node());
node = node.children.get(p);
ans += node.cnt;
}
++node.cnt;
}
return ans;
}
}
```

```cpp
class Node {
public:
unordered_map<int, Node*> children;
int cnt;

Node()
: cnt(0) {}
};

class Solution {
public:
int countPrefixSuffixPairs(vector<string>& words) {
int ans = 0;
Node* trie = new Node();
for (const string& s : words) {
Node* node = trie;
int m = s.length();
for (int i = 0; i < m; ++i) {
int p = s[i] * 32 + s[m - i - 1];
if (node->children.find(p) == node->children.end()) {
node->children[p] = new Node();
}
node = node->children[p];
ans += node->cnt;
}
++node->cnt;
}
return ans;
}
};
```

```go
type Node struct {
children map[int]*Node
cnt int
}

func countPrefixSuffixPairs(words []string) (ans int) {
trie := &Node{children: make(map[int]*Node)}
for _, s := range words {
node := trie
m := len(s)
for i := 0; i < m; i++ {
p := int(s[i])*32 + int(s[m-i-1])
if _, ok := node.children[p]; !ok {
node.children[p] = &Node{children: make(map[int]*Node)}
}
node = node.children[p]
ans += node.cnt
}
node.cnt++
}
return
}
```

<!-- tabs:end -->
Expand Down
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