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Commit 0070599

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feat: add solutions to lc/lcof2 problem: Asteroid Collision
1 parent 92e73c3 commit 0070599

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11 files changed

+410
-31
lines changed

11 files changed

+410
-31
lines changed

‎lcof2/剑指 Offer II 037. 小行星碰撞/README.md‎

Lines changed: 89 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -59,22 +59,110 @@
5959

6060
<!-- 这里可写通用的实现逻辑 -->
6161

62+
可以类比成左右括号匹配:
63+
64+
- 向右移动的小行星(左括号):不会引发碰撞,直接入栈
65+
- 向左移动的小行星(右括号):可能会和之前向右移动的小行星发生碰撞,特殊处理
66+
67+
因为答案需要碰撞后剩下的所有小行星,相当于栈里最后剩下的元素,所以可以直接用数组表示栈
68+
6269
<!-- tabs:start -->
6370

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### **Python3**
6572

6673
<!-- 这里可写当前语言的特殊实现逻辑 -->
6774

6875
```python
69-
76+
class Solution:
77+
def asteroidCollision(self, asteroids: List[int]) -> List[int]:
78+
ans = []
79+
for a in asteroids:
80+
if a > 0:
81+
ans.append(a)
82+
else:
83+
while len(ans) > 0 and ans[-1] > 0 and ans[-1] < -a:
84+
ans.pop()
85+
if len(ans) > 0 and ans[-1] == -a:
86+
ans.pop()
87+
elif len(ans) == 0 or ans[-1] < -a:
88+
ans.append(a)
89+
return ans
7090
```
7191

7292
### **Java**
7393

7494
<!-- 这里可写当前语言的特殊实现逻辑 -->
7595

7696
```java
97+
class Solution {
98+
public int[] asteroidCollision(int[] asteroids) {
99+
Deque<Integer> d = new ArrayDeque<>();
100+
for (int a : asteroids) {
101+
if (a > 0) {
102+
d.offerLast(a);
103+
} else {
104+
while (!d.isEmpty() && d.peekLast() > 0 && d.peekLast() < -a) {
105+
d.pollLast();
106+
}
107+
if (!d.isEmpty() && d.peekLast() == -a) {
108+
d.pollLast();
109+
} else if (d.isEmpty() || d.peekLast() < -a) {
110+
d.offerLast(a);
111+
}
112+
}
113+
}
114+
return d.stream().mapToInt(Integer::valueOf).toArray();
115+
}
116+
}
117+
```
118+
119+
### **C++**
120+
121+
```cpp
122+
class Solution {
123+
public:
124+
vector<int> asteroidCollision(vector<int>& asteroids) {
125+
vector<int> ans;
126+
for (int a : asteroids) {
127+
if (a > 0) {
128+
ans.push_back(a);
129+
} else {
130+
while (!ans.empty() && ans.back() > 0 && ans.back() < -a) {
131+
ans.pop_back();
132+
}
133+
if (!ans.empty() && ans.back() == -a) {
134+
ans.pop_back();
135+
} else if (ans.empty() || ans.back() < -a) {
136+
ans.push_back(a);
137+
}
138+
}
139+
}
140+
return ans;
141+
}
142+
};
143+
```
77144
145+
### **Go**
146+
147+
```go
148+
func asteroidCollision(asteroids []int) []int {
149+
var ans []int
150+
for _, a := range asteroids {
151+
if a > 0 {
152+
ans = append(ans, a)
153+
} else {
154+
for len(ans) > 0 && ans[len(ans)-1] > 0 && ans[len(ans)-1] < -a {
155+
ans = ans[:len(ans)-1]
156+
}
157+
if len(ans) > 0 && ans[len(ans)-1] == -a {
158+
ans = ans[:len(ans)-1]
159+
} else if len(ans) == 0 || ans[len(ans)-1] < -a {
160+
ans = append(ans, a)
161+
}
162+
}
163+
}
164+
return ans
165+
}
78166
```
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### **...**
Lines changed: 21 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,21 @@
1+
class Solution {
2+
public:
3+
vector<int> asteroidCollision(vector<int>& asteroids) {
4+
vector<int> ans;
5+
for (int a : asteroids) {
6+
if (a > 0) {
7+
ans.push_back(a);
8+
} else {
9+
while (!ans.empty() && ans.back() > 0 && ans.back() < -a) {
10+
ans.pop_back();
11+
}
12+
if (!ans.empty() && ans.back() == -a) {
13+
ans.pop_back();
14+
} else if (ans.empty() || ans.back() < -a) {
15+
ans.push_back(a);
16+
}
17+
}
18+
}
19+
return ans;
20+
}
21+
};
Lines changed: 18 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,18 @@
1+
func asteroidCollision(asteroids []int) []int {
2+
var ans []int
3+
for _, a := range asteroids {
4+
if a > 0 {
5+
ans = append(ans, a)
6+
} else {
7+
for len(ans) > 0 && ans[len(ans)-1] > 0 && ans[len(ans)-1] < -a {
8+
ans = ans[:len(ans)-1]
9+
}
10+
if len(ans) > 0 && ans[len(ans)-1] == -a {
11+
ans = ans[:len(ans)-1]
12+
} else if len(ans) == 0 || ans[len(ans)-1] < -a {
13+
ans = append(ans, a)
14+
}
15+
}
16+
}
17+
return ans
18+
}
Lines changed: 20 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,20 @@
1+
class Solution {
2+
public int[] asteroidCollision(int[] asteroids) {
3+
Deque<Integer> d = new ArrayDeque<>();
4+
for (int a : asteroids) {
5+
if (a > 0) {
6+
d.offerLast(a);
7+
} else {
8+
while (!d.isEmpty() && d.peekLast() > 0 && d.peekLast() < -a) {
9+
d.pollLast();
10+
}
11+
if (!d.isEmpty() && d.peekLast() == -a) {
12+
d.pollLast();
13+
} else if (d.isEmpty() || d.peekLast() < -a) {
14+
d.offerLast(a);
15+
}
16+
}
17+
}
18+
return d.stream().mapToInt(Integer::valueOf).toArray();
19+
}
20+
}
Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,14 @@
1+
class Solution:
2+
def asteroidCollision(self, asteroids: List[int]) -> List[int]:
3+
ans = []
4+
for a in asteroids:
5+
if a > 0:
6+
ans.append(a)
7+
else:
8+
while len(ans) > 0 and ans[-1] > 0 and ans[-1] < -a:
9+
ans.pop()
10+
if len(ans) > 0 and ans[-1] == -a:
11+
ans.pop()
12+
elif len(ans) == 0 or ans[-1] < -a:
13+
ans.append(a)
14+
return ans

‎solution/0700-0799/0735.Asteroid Collision/README.md‎

Lines changed: 89 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -57,22 +57,110 @@
5757

5858
<!-- 这里可写通用的实现逻辑 -->
5959

60+
可以类比成左右括号匹配:
61+
62+
- 向右移动的小行星(左括号):不会引发碰撞,直接入栈
63+
- 向左移动的小行星(右括号):可能会和之前向右移动的小行星发生碰撞,特殊处理
64+
65+
因为答案需要碰撞后剩下的所有小行星,相当于栈里最后剩下的元素,所以可以直接用数组表示栈
66+
6067
<!-- tabs:start -->
6168

6269
### **Python3**
6370

6471
<!-- 这里可写当前语言的特殊实现逻辑 -->
6572

6673
```python
67-
74+
class Solution:
75+
def asteroidCollision(self, asteroids: List[int]) -> List[int]:
76+
ans = []
77+
for a in asteroids:
78+
if a > 0:
79+
ans.append(a)
80+
else:
81+
while len(ans) > 0 and ans[-1] > 0 and ans[-1] < -a:
82+
ans.pop()
83+
if len(ans) > 0 and ans[-1] == -a:
84+
ans.pop()
85+
elif len(ans) == 0 or ans[-1] < -a:
86+
ans.append(a)
87+
return ans
6888
```
6989

7090
### **Java**
7191

7292
<!-- 这里可写当前语言的特殊实现逻辑 -->
7393

7494
```java
95+
class Solution {
96+
public int[] asteroidCollision(int[] asteroids) {
97+
Deque<Integer> d = new ArrayDeque<>();
98+
for (int a : asteroids) {
99+
if (a > 0) {
100+
d.offerLast(a);
101+
} else {
102+
while (!d.isEmpty() && d.peekLast() > 0 && d.peekLast() < -a) {
103+
d.pollLast();
104+
}
105+
if (!d.isEmpty() && d.peekLast() == -a) {
106+
d.pollLast();
107+
} else if (d.isEmpty() || d.peekLast() < -a) {
108+
d.offerLast(a);
109+
}
110+
}
111+
}
112+
return d.stream().mapToInt(Integer::valueOf).toArray();
113+
}
114+
}
115+
```
116+
117+
### **C++**
118+
119+
```cpp
120+
class Solution {
121+
public:
122+
vector<int> asteroidCollision(vector<int>& asteroids) {
123+
vector<int> ans;
124+
for (int a : asteroids) {
125+
if (a > 0) {
126+
ans.push_back(a);
127+
} else {
128+
while (!ans.empty() && ans.back() > 0 && ans.back() < -a) {
129+
ans.pop_back();
130+
}
131+
if (!ans.empty() && ans.back() == -a) {
132+
ans.pop_back();
133+
} else if (ans.empty() || ans.back() < -a) {
134+
ans.push_back(a);
135+
}
136+
}
137+
}
138+
return ans;
139+
}
140+
};
141+
```
75142
143+
### **Go**
144+
145+
```go
146+
func asteroidCollision(asteroids []int) []int {
147+
var ans []int
148+
for _, a := range asteroids {
149+
if a > 0 {
150+
ans = append(ans, a)
151+
} else {
152+
for len(ans) > 0 && ans[len(ans)-1] > 0 && ans[len(ans)-1] < -a {
153+
ans = ans[:len(ans)-1]
154+
}
155+
if len(ans) > 0 && ans[len(ans)-1] == -a {
156+
ans = ans[:len(ans)-1]
157+
} else if len(ans) == 0 || ans[len(ans)-1] < -a {
158+
ans = append(ans, a)
159+
}
160+
}
161+
}
162+
return ans
163+
}
76164
```
77165

78166
### **...**

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