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feat: add solutions to lc problem: No.0241
No.0241.Different Ways to Add Parentheses
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6 files changed

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‎solution/0200-0299/0241.Different Ways to Add Parentheses/README.md

Lines changed: 140 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -49,22 +49,161 @@
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<!-- 这里可写通用的实现逻辑 -->
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**方法一：记忆化搜索**
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<!-- tabs:start -->
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### **Python3**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```python
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class Solution:
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def diffWaysToCompute(self, expression: str) -> List[int]:
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@cache
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def dfs(exp):
65+
if exp.isdigit():
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return [int(exp)]
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ans = []
68+
for i, c in enumerate(exp):
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if c in '-+*':
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left, right = dfs(exp[:i]), dfs(exp[i + 1:])
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for a in left:
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for b in right:
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if c == '-':
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ans.append(a - b)
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elif c == '+':
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ans.append(a + b)
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else:
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ans.append(a * b)
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return ans
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return dfs(expression)
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```
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### **Java**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```java
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class Solution {
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private static Map<String, List<Integer>> memo = new HashMap<>();
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public List<Integer> diffWaysToCompute(String expression) {
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return dfs(expression);
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}
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private List<Integer> dfs(String exp) {
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if (memo.containsKey(exp)) {
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return memo.get(exp);
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}
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List<Integer> ans = new ArrayList<>();
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if (exp.length() < 3) {
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ans.add(Integer.parseInt(exp));
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return ans;
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}
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for (int i = 0; i < exp.length(); ++i) {
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char c = exp.charAt(i);
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if (c == '-' || c == '+' || c == '*') {
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List<Integer> left = dfs(exp.substring(0, i));
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List<Integer> right = dfs(exp.substring(i + 1));
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for (int a : left) {
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for (int b : right) {
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if (c == '-') {
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ans.add(a - b);
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} else if (c == '+') {
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ans.add(a + b);
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} else {
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ans.add(a * b);
118+
}
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}
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}
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}
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}
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memo.put(exp, ans);
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return ans;
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}
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}
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```
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### **C++**
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```cpp
132+
class Solution {
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public:
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vector<int> diffWaysToCompute(string expression) {
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return dfs(expression);
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}
137+
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vector<int> dfs(string exp) {
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if (memo.count(exp)) return memo[exp];
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if (exp.size() < 3) return {stoi(exp)};
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vector<int> ans;
142+
int n = exp.size();
143+
for (int i = 0; i < n; ++i)
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{
145+
char c = exp[i];
146+
if (c == '-' || c == '+' || c == '*')
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{
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vector<int> left = dfs(exp.substr(0, i));
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vector<int> right = dfs(exp.substr(i + 1, n - i - 1));
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for (int& a : left)
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{
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for (int& b : right)
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{
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if (c == '-') ans.push_back(a - b);
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else if (c == '+') ans.push_back(a + b);
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else ans.push_back(a * b);
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}
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}
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}
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}
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memo[exp] = ans;
162+
return ans;
163+
}
164+
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private:
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unordered_map<string, vector<int>> memo;
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};
168+
```
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170+
### **Go**
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```go
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var memo = map[string][]int{}
174+
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func diffWaysToCompute(expression string) []int {
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return dfs(expression)
177+
}
178+
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func dfs(exp string) []int {
180+
if v, ok := memo[exp]; ok {
181+
return v
182+
}
183+
if len(exp) < 3 {
184+
v, _ := strconv.Atoi(exp)
185+
return []int{v}
186+
}
187+
ans := []int{}
188+
for i, c := range exp {
189+
if c == '-' || c == '+' || c == '*' {
190+
left, right := dfs(exp[:i]), dfs(exp[i+1:])
191+
for _, a := range left {
192+
for _, b := range right {
193+
if c == '-' {
194+
ans = append(ans, a-b)
195+
} else if c == '+' {
196+
ans = append(ans, a+b)
197+
} else {
198+
ans = append(ans, a*b)
199+
}
200+
}
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}
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}
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}
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memo[exp] = ans
205+
return ans
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}
68207
```
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### **...**

‎solution/0200-0299/0241.Different Ways to Add Parentheses/README_EN.md

Lines changed: 138 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -48,13 +48,150 @@
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### **Python3**
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```python
51-
51+
class Solution:
52+
def diffWaysToCompute(self, expression: str) -> List[int]:
53+
@cache
54+
def dfs(exp):
55+
if exp.isdigit():
56+
return [int(exp)]
57+
ans = []
58+
for i, c in enumerate(exp):
59+
if c in '-+*':
60+
left, right = dfs(exp[:i]), dfs(exp[i + 1:])
61+
for a in left:
62+
for b in right:
63+
if c == '-':
64+
ans.append(a - b)
65+
elif c == '+':
66+
ans.append(a + b)
67+
else:
68+
ans.append(a * b)
69+
return ans
70+
71+
return dfs(expression)
5272
```
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5474
### **Java**
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```java
77+
class Solution {
78+
private static Map<String, List<Integer>> memo = new HashMap<>();
79+
80+
public List<Integer> diffWaysToCompute(String expression) {
81+
return dfs(expression);
82+
}
83+
84+
private List<Integer> dfs(String exp) {
85+
if (memo.containsKey(exp)) {
86+
return memo.get(exp);
87+
}
88+
List<Integer> ans = new ArrayList<>();
89+
if (exp.length() < 3) {
90+
ans.add(Integer.parseInt(exp));
91+
return ans;
92+
}
93+
for (int i = 0; i < exp.length(); ++i) {
94+
char c = exp.charAt(i);
95+
if (c == '-' || c == '+' || c == '*') {
96+
List<Integer> left = dfs(exp.substring(0, i));
97+
List<Integer> right = dfs(exp.substring(i + 1));
98+
for (int a : left) {
99+
for (int b : right) {
100+
if (c == '-') {
101+
ans.add(a - b);
102+
} else if (c == '+') {
103+
ans.add(a + b);
104+
} else {
105+
ans.add(a * b);
106+
}
107+
}
108+
}
109+
}
110+
}
111+
memo.put(exp, ans);
112+
return ans;
113+
}
114+
}
115+
```
116+
117+
### **C++**
118+
119+
```cpp
120+
class Solution {
121+
public:
122+
vector<int> diffWaysToCompute(string expression) {
123+
return dfs(expression);
124+
}
125+
126+
vector<int> dfs(string exp) {
127+
if (memo.count(exp)) return memo[exp];
128+
if (exp.size() < 3) return {stoi(exp)};
129+
vector<int> ans;
130+
int n = exp.size();
131+
for (int i = 0; i < n; ++i)
132+
{
133+
char c = exp[i];
134+
if (c == '-' || c == '+' || c == '*')
135+
{
136+
vector<int> left = dfs(exp.substr(0, i));
137+
vector<int> right = dfs(exp.substr(i + 1, n - i - 1));
138+
for (int& a : left)
139+
{
140+
for (int& b : right)
141+
{
142+
if (c == '-') ans.push_back(a - b);
143+
else if (c == '+') ans.push_back(a + b);
144+
else ans.push_back(a * b);
145+
}
146+
}
147+
}
148+
}
149+
memo[exp] = ans;
150+
return ans;
151+
}
152+
153+
private:
154+
unordered_map<string, vector<int>> memo;
155+
};
156+
```
57157

158+
### **Go**
159+
160+
```go
161+
var memo = map[string][]int{}
162+
163+
func diffWaysToCompute(expression string) []int {
164+
return dfs(expression)
165+
}
166+
167+
func dfs(exp string) []int {
168+
if v, ok := memo[exp]; ok {
169+
return v
170+
}
171+
if len(exp) < 3 {
172+
v, _ := strconv.Atoi(exp)
173+
return []int{v}
174+
}
175+
ans := []int{}
176+
for i, c := range exp {
177+
if c == '-' || c == '+' || c == '*' {
178+
left, right := dfs(exp[:i]), dfs(exp[i+1:])
179+
for _, a := range left {
180+
for _, b := range right {
181+
if c == '-' {
182+
ans = append(ans, a-b)
183+
} else if c == '+' {
184+
ans = append(ans, a+b)
185+
} else {
186+
ans = append(ans, a*b)
187+
}
188+
}
189+
}
190+
}
191+
}
192+
memo[exp] = ans
193+
return ans
194+
}
58195
```
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### **...**

‎solution/0200-0299/0241.Different Ways to Add Parentheses/Solution.cpp

Lines changed: 36 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,36 @@
1+
class Solution {
2+
public:
3+
vector<int> diffWaysToCompute(string expression) {
4+
return dfs(expression);
5+
}
6+
7+
vector<int> dfs(string exp) {
8+
if (memo.count(exp)) return memo[exp];
9+
if (exp.size() < 3) return {stoi(exp)};
10+
vector<int> ans;
11+
int n = exp.size();
12+
for (int i = 0; i < n; ++i)
13+
{
14+
char c = exp[i];
15+
if (c == '-' || c == '+' || c == '*')
16+
{
17+
vector<int> left = dfs(exp.substr(0, i));
18+
vector<int> right = dfs(exp.substr(i + 1, n - i - 1));
19+
for (int& a : left)
20+
{
21+
for (int& b : right)
22+
{
23+
if (c == '-') ans.push_back(a - b);
24+
else if (c == '+') ans.push_back(a + b);
25+
else ans.push_back(a * b);
26+
}
27+
}
28+
}
29+
}
30+
memo[exp] = ans;
31+
return ans;
32+
}
33+
34+
private:
35+
unordered_map<string, vector<int>> memo;
36+
};

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