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Commit 093a0b6

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feat: add solutions to lc problem: No.2210,2211 (#767)
- No.2210.Count Hills and Valleys in an Array - No.2211.Count Collisions on a Road
1 parent 60d2cef commit 093a0b6

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9 files changed

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-16
lines changed

9 files changed

+252
-16
lines changed

‎solution/2200-2299/2210.Count Hills and Valleys in an Array/README.md‎

Lines changed: 42 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -56,22 +56,62 @@
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<!-- 这里可写通用的实现逻辑 -->
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59+
先处理数组 `nums`,把连续的都变成一个,比如 `[6, 6, 5, 5, 4, 1]`,转换为 `[6, 5, 4, 1]` 之后,再进行比较。
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61+
优化:
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可以使用双指针的方式,忽略相邻重复的元素,而无需改动原数组。
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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
66-
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class Solution:
73+
def countHillValley(self, nums: List[int]) -> int:
74+
count = 0
75+
pt = 0
76+
while pt < len(nums)-1:
77+
if nums[pt] == nums[pt+1]:
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nums.pop(pt)
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continue
80+
else:
81+
pt += 1
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for i in range(1, len(nums)-1):
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if nums[i] < nums[i+1] and nums[i-1] > nums[i]:
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count += 1
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continue
86+
elif nums[i] > nums[i+1] and nums[i] > nums[i-1]:
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count += 1
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continue
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return count
6790
```
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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
74-
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class Solution {
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public int countHillValley(int[] nums) {
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int count = 0;
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for(int i = 1,j = 0; i < nums.length-1; i++) {
101+
if(nums[i] == nums[i+1]) {
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continue;
103+
}
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if(nums[i] > nums[j] && nums[i] > nums[i+1]) {
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count++;
106+
}
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if(nums[i] < nums[j] && nums[i] < nums[i+1]){
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count++;
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}
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j = i;
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}
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return count;
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}
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}
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```
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### **TypeScript**

‎solution/2200-2299/2210.Count Hills and Valleys in an Array/README_EN.md‎

Lines changed: 38 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -54,15 +54,51 @@ There are 0 hills and valleys so we return 0.
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<!-- tabs:start -->
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### **Python3**
57+
First make the consecutive duplicate value to be unique with the side values.
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```python
59-
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class Solution:
61+
def countHillValley(self, nums: List[int]) -> int:
62+
count = 0
63+
pt = 0
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while pt < len(nums)-1:
65+
if nums[pt] == nums[pt+1]:
66+
nums.pop(pt)
67+
continue
68+
else:
69+
pt += 1
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for i in range(1, len(nums)-1):
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if nums[i] < nums[i+1] and nums[i-1] > nums[i]:
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count += 1
73+
continue
74+
elif nums[i] > nums[i+1] and nums[i] > nums[i-1]:
75+
count += 1
76+
continue
77+
return count
6078
```
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### **Java**
81+
Use two pointers to solve the problem
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```java
65-
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class Solution {
85+
public int countHillValley(int[] nums) {
86+
int count = 0;
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for(int i = 1,j = 0; i < nums.length-1; i++) {
88+
if(nums[i] == nums[i+1]) {
89+
continue;
90+
}
91+
if(nums[i] > nums[j] && nums[i] > nums[i+1]) {
92+
count++;
93+
}
94+
if(nums[i] < nums[j] && nums[i] < nums[i+1]){
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count++;
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}
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j = i;
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}
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return count;
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}
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}
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```
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### **TypeScript**
Lines changed: 18 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,18 @@
1+
class Solution {
2+
public int countHillValley(int[] nums) {
3+
int count = 0;
4+
for (int i = 1, j = 0; i < nums.length - 1; i++) {
5+
if(nums[i] == nums[i+1]) {
6+
continue;
7+
}
8+
if(nums[i] > nums[j] && nums[i] > nums[i+1]) {
9+
count++;
10+
}
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if(nums[i] < nums[j] && nums[i] < nums[i+1]){
12+
count++;
13+
}
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j = i;
15+
}
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return count;
17+
}
18+
}
Lines changed: 18 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,18 @@
1+
class Solution:
2+
def countHillValley(self, nums: List[int]) -> int:
3+
count = 0
4+
pt = 0
5+
while pt < len(nums)-1:
6+
if nums[pt] == nums[pt+1]:
7+
nums.pop(pt)
8+
continue
9+
else:
10+
pt += 1
11+
for i in range(1, len(nums)-1):
12+
if nums[i] < nums[i+1] and nums[i-1] > nums[i]:
13+
count += 1
14+
continue
15+
elif nums[i] > nums[i+1] and nums[i] > nums[i-1]:
16+
count += 1
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continue
18+
return count

‎solution/2200-2299/2211.Count Collisions on a Road/README.md‎

Lines changed: 47 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -57,6 +57,7 @@
5757
## 解法
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<!-- 这里可写通用的实现逻辑 -->
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这个题比较有意思,最后规律是左边向左的车辆可以出去,右边向右的车辆可以出去,中间不是S的都出不来
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<!-- tabs:start -->
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@@ -65,15 +66,39 @@
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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:
70+
def countCollisions(self, directions: str) -> int:
71+
l, r = 0, len(directions)-1
72+
while l <= r and directions[l] == 'L':
73+
l += 1
74+
while l <= r and directions[r] == 'R':
75+
r -= 1
76+
count = 0
77+
for i in range(l, r+1):
78+
count += directions[i] != 'S'
79+
return count
6980
```
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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
76-
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class Solution {
88+
public int countCollisions(String directions) {
89+
int l = 0, r = directions.length() -1, count = 0;
90+
while (l <= r && directions.substring(l, l+1).equals("L")) {
91+
l++;
92+
}
93+
while (l <= r && directions.substring(r, r+1).equals("R")) {
94+
r--;
95+
}
96+
for (int i = l; i <=r; i++) {
97+
if (!directions.substring(i, i+1).equals("S")) count += 1;
98+
}
99+
return count;
100+
}
101+
}
77102
```
78103

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### **TypeScript**
@@ -82,10 +107,26 @@
82107

83108
```
84109

85-
### **...**
86-
87-
```
88-
110+
### **C++**
111+
112+
```cpp
113+
class Solution {
114+
public:
115+
int countCollisions(string directions) {
116+
int l = 0, r = directions.size() -1, count = 0;
117+
while (l <= r && directions[l] == 'L') {
118+
l++;
119+
}
120+
while (l <= r && directions[r] == 'R') {
121+
r--;
122+
}
123+
for (int i = l; i <=r; i++) {
124+
count += directions[i] != 'S';
125+
}
126+
return count;
127+
128+
}
129+
};
89130
```
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<!-- tabs:end -->

‎solution/2200-2299/2211.Count Collisions on a Road/README_EN.md‎

Lines changed: 46 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -57,13 +57,37 @@ No cars will collide with each other. Thus, the total number of collisions that
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### **Python3**
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```python
60-
60+
class Solution:
61+
def countCollisions(self, directions: str) -> int:
62+
l, r = 0, len(directions)-1
63+
while l <= r and directions[l] == 'L':
64+
l += 1
65+
while l <= r and directions[r] == 'R':
66+
r -= 1
67+
count = 0
68+
for i in range(l, r+1):
69+
count += directions[i] != 'S'
70+
return count
6171
```
6272

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### **Java**
6474

6575
```java
66-
76+
class Solution {
77+
public int countCollisions(String directions) {
78+
int l = 0, r = directions.length() -1, count = 0;
79+
while (l <= r && directions.substring(l, l+1).equals("L")) {
80+
l++;
81+
}
82+
while (l <= r && directions.substring(r, r+1).equals("R")) {
83+
r--;
84+
}
85+
for (int i = l; i <=r; i++) {
86+
if (!directions.substring(i, i+1).equals("S")) count += 1;
87+
}
88+
return count;
89+
}
90+
}
6791
```
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### **TypeScript**
@@ -72,10 +96,26 @@ No cars will collide with each other. Thus, the total number of collisions that
7296

7397
```
7498

75-
### **...**
76-
77-
```
78-
99+
### **C++**
100+
101+
```cpp
102+
class Solution {
103+
public:
104+
int countCollisions(string directions) {
105+
int l = 0, r = directions.size() -1, count = 0;
106+
while (l <= r && directions[l] == 'L') {
107+
l++;
108+
}
109+
while (l <= r && directions[r] == 'R') {
110+
r--;
111+
}
112+
for (int i = l; i <=r; i++) {
113+
count += directions[i] != 'S';
114+
}
115+
return count;
116+
117+
}
118+
};
79119
```
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<!-- tabs:end -->
Lines changed: 17 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,17 @@
1+
class Solution {
2+
public:
3+
int countCollisions(string directions) {
4+
int l = 0, r = directions.size() -1, count = 0;
5+
while (l <= r && directions[l] == 'L') {
6+
l++;
7+
}
8+
while (l <= r && directions[r] == 'R') {
9+
r--;
10+
}
11+
for (int i = l; i <=r; i++) {
12+
count += directions[i] != 'S';
13+
}
14+
return count;
15+
16+
}
17+
};
Lines changed: 15 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,15 @@
1+
class Solution {
2+
public int countCollisions(String directions) {
3+
int l = 0, r = directions.length() -1, count = 0;
4+
while (l <= r && directions.substring(l, l+1).equals("L")) {
5+
l++;
6+
}
7+
while (l <= r && directions.substring(r, r+1).equals("R")) {
8+
r--;
9+
}
10+
for (int i = l; i <=r; i++) {
11+
if (!directions.substring(i, i+1).equals("S")) count += 1;
12+
}
13+
return count;
14+
}
15+
}
Lines changed: 11 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,11 @@
1+
class Solution:
2+
def countCollisions(self, directions: str) -> int:
3+
l, r = 0, len(directions)-1
4+
while l <= r and directions[l] == 'L':
5+
l += 1
6+
while l <= r and directions[r] == 'R':
7+
r -= 1
8+
count = 0
9+
for i in range(l, r+1):
10+
count += directions[i] != 'S'
11+
return count

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