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Commit d4a75dc

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feat: add solutions to lc problem: No.2210
No.2210.Count Hills and Valleys in an Array
1 parent fcdfa34 commit d4a75dc

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6 files changed

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-61
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6 files changed

+173
-61
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‎solution/2200-2299/2210.Count Hills and Valleys in an Array/README.md‎

Lines changed: 64 additions & 20 deletions
Original file line numberDiff line numberDiff line change
@@ -71,22 +71,26 @@
7171
```python
7272
class Solution:
7373
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]:
78-
nums.pop(pt)
79-
continue
80-
else:
81-
pt += 1
82-
for i in range(1, len(nums)-1):
83-
if nums[i] < nums[i+1] and nums[i-1] > nums[i]:
84-
count += 1
85-
continue
86-
elif nums[i] > nums[i+1] and nums[i] > nums[i-1]:
87-
count += 1
74+
arr = [nums[0]]
75+
for v in nums[1:]:
76+
if v != arr[-1]:
77+
arr.append(v)
78+
return sum((arr[i] < arr[i - 1]) == (arr[i] < arr[i + 1]) for i in range(1, len(arr) - 1))
79+
```
80+
81+
```python
82+
class Solution:
83+
def countHillValley(self, nums: List[int]) -> int:
84+
ans = j = 0
85+
for i in range(1, len(nums) - 1):
86+
if nums[i] == nums[i + 1]:
8887
continue
89-
return count
88+
if nums[i] > nums[j] and nums[i] > nums[i + 1]:
89+
ans += 1
90+
if nums[i] < nums[j] and nums[i] < nums[i + 1]:
91+
ans += 1
92+
j = i
93+
return ans
9094
```
9195

9296
### **Java**
@@ -96,24 +100,64 @@ class Solution:
96100
```java
97101
class Solution {
98102
public int countHillValley(int[] nums) {
99-
int count = 0;
100-
for (int i = 1, j = 0; i < nums.length - 1; i++) {
103+
int ans = 0;
104+
for (int i = 1, j = 0; i < nums.length - 1; ++i) {
101105
if (nums[i] == nums[i + 1]) {
102106
continue;
103107
}
104108
if (nums[i] > nums[j] && nums[i] > nums[i + 1]) {
105-
count++;
109+
++ans;
106110
}
107111
if (nums[i] < nums[j] && nums[i] < nums[i + 1]) {
108-
count++;
112+
++ans;
109113
}
110114
j = i;
111115
}
112-
return count;
116+
return ans;
113117
}
114118
}
115119
```
116120

121+
### **C++**
122+
123+
```cpp
124+
class Solution {
125+
public:
126+
int countHillValley(vector<int>& nums) {
127+
int ans = 0;
128+
for (int i = 1, j = 0; i < nums.size() - 1; ++i)
129+
{
130+
if (nums[i] == nums[i + 1]) continue;
131+
if (nums[i] > nums[j] && nums[i] > nums[i + 1]) ++ans;
132+
if (nums[i] < nums[j] && nums[i] < nums[i + 1]) ++ans;
133+
j = i;
134+
}
135+
return ans;
136+
}
137+
};
138+
```
139+
140+
### **Go**
141+
142+
```go
143+
func countHillValley(nums []int) int {
144+
ans := 0
145+
for i, j := 1, 0; i < len(nums)-1; i++ {
146+
if nums[i] == nums[i+1] {
147+
continue
148+
}
149+
if nums[i] > nums[j] && nums[i] > nums[i+1] {
150+
ans++
151+
}
152+
if nums[i] < nums[j] && nums[i] < nums[i+1] {
153+
ans++
154+
}
155+
j = i
156+
}
157+
return ans
158+
}
159+
```
160+
117161
### **TypeScript**
118162

119163
```ts

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

Lines changed: 64 additions & 20 deletions
Original file line numberDiff line numberDiff line change
@@ -60,22 +60,26 @@ First make the consecutive duplicate value to be unique with the side values.
6060
```python
6161
class Solution:
6262
def countHillValley(self, nums: List[int]) -> int:
63-
count = 0
64-
pt = 0
65-
while pt < len(nums)-1:
66-
if nums[pt] == nums[pt+1]:
67-
nums.pop(pt)
68-
continue
69-
else:
70-
pt += 1
71-
for i in range(1, len(nums)-1):
72-
if nums[i] < nums[i+1] and nums[i-1] > nums[i]:
73-
count += 1
74-
continue
75-
elif nums[i] > nums[i+1] and nums[i] > nums[i-1]:
76-
count += 1
63+
arr = [nums[0]]
64+
for v in nums[1:]:
65+
if v != arr[-1]:
66+
arr.append(v)
67+
return sum((arr[i] < arr[i - 1]) == (arr[i] < arr[i + 1]) for i in range(1, len(arr) - 1))
68+
```
69+
70+
```python
71+
class Solution:
72+
def countHillValley(self, nums: List[int]) -> int:
73+
ans = j = 0
74+
for i in range(1, len(nums) - 1):
75+
if nums[i] == nums[i + 1]:
7776
continue
78-
return count
77+
if nums[i] > nums[j] and nums[i] > nums[i + 1]:
78+
ans += 1
79+
if nums[i] < nums[j] and nums[i] < nums[i + 1]:
80+
ans += 1
81+
j = i
82+
return ans
7983
```
8084

8185
### **Java**
@@ -85,24 +89,64 @@ Use two pointers to solve the problem
8589
```java
8690
class Solution {
8791
public int countHillValley(int[] nums) {
88-
int count = 0;
89-
for (int i = 1, j = 0; i < nums.length - 1; i++) {
92+
int ans = 0;
93+
for (int i = 1, j = 0; i < nums.length - 1; ++i) {
9094
if (nums[i] == nums[i + 1]) {
9195
continue;
9296
}
9397
if (nums[i] > nums[j] && nums[i] > nums[i + 1]) {
94-
count++;
98+
++ans;
9599
}
96100
if (nums[i] < nums[j] && nums[i] < nums[i + 1]) {
97-
count++;
101+
++ans;
98102
}
99103
j = i;
100104
}
101-
return count;
105+
return ans;
102106
}
103107
}
104108
```
105109

110+
### **C++**
111+
112+
```cpp
113+
class Solution {
114+
public:
115+
int countHillValley(vector<int>& nums) {
116+
int ans = 0;
117+
for (int i = 1, j = 0; i < nums.size() - 1; ++i)
118+
{
119+
if (nums[i] == nums[i + 1]) continue;
120+
if (nums[i] > nums[j] && nums[i] > nums[i + 1]) ++ans;
121+
if (nums[i] < nums[j] && nums[i] < nums[i + 1]) ++ans;
122+
j = i;
123+
}
124+
return ans;
125+
}
126+
};
127+
```
128+
129+
### **Go**
130+
131+
```go
132+
func countHillValley(nums []int) int {
133+
ans := 0
134+
for i, j := 1, 0; i < len(nums)-1; i++ {
135+
if nums[i] == nums[i+1] {
136+
continue
137+
}
138+
if nums[i] > nums[j] && nums[i] > nums[i+1] {
139+
ans++
140+
}
141+
if nums[i] < nums[j] && nums[i] < nums[i+1] {
142+
ans++
143+
}
144+
j = i
145+
}
146+
return ans
147+
}
148+
```
149+
106150
### **TypeScript**
107151

108152
```ts
Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,14 @@
1+
class Solution {
2+
public:
3+
int countHillValley(vector<int>& nums) {
4+
int ans = 0;
5+
for (int i = 1, j = 0; i < nums.size() - 1; ++i)
6+
{
7+
if (nums[i] == nums[i + 1]) continue;
8+
if (nums[i] > nums[j] && nums[i] > nums[i + 1]) ++ans;
9+
if (nums[i] < nums[j] && nums[i] < nums[i + 1]) ++ans;
10+
j = i;
11+
}
12+
return ans;
13+
}
14+
};
Lines changed: 16 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,16 @@
1+
func countHillValley(nums []int) int {
2+
ans := 0
3+
for i, j := 1, 0; i < len(nums)-1; i++ {
4+
if nums[i] == nums[i+1] {
5+
continue
6+
}
7+
if nums[i] > nums[j] && nums[i] > nums[i+1] {
8+
ans++
9+
}
10+
if nums[i] < nums[j] && nums[i] < nums[i+1] {
11+
ans++
12+
}
13+
j = i
14+
}
15+
return ans
16+
}
Lines changed: 6 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -1,18 +1,18 @@
11
class Solution {
22
public int countHillValley(int[] nums) {
3-
int count = 0;
4-
for (int i = 1, j = 0; i < nums.length - 1; i++) {
3+
int ans = 0;
4+
for (int i = 1, j = 0; i < nums.length - 1; ++i) {
55
if (nums[i] == nums[i + 1]) {
66
continue;
77
}
88
if (nums[i] > nums[j] && nums[i] > nums[i + 1]) {
9-
count++;
9+
++ans;
1010
}
1111
if (nums[i] < nums[j] && nums[i] < nums[i + 1]) {
12-
count++;
12+
++ans;
1313
}
1414
j = i;
1515
}
16-
return count;
16+
return ans;
1717
}
18-
}
18+
}
Lines changed: 9 additions & 15 deletions
Original file line numberDiff line numberDiff line change
@@ -1,18 +1,12 @@
11
class Solution:
22
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)
3+
ans = j = 0
4+
for i in range(1, len(nums) - 1):
5+
if nums[i] == nums[i + 1]:
86
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
17-
continue
18-
return count
7+
if nums[i] > nums[j] and nums[i] > nums[i + 1]:
8+
ans += 1
9+
if nums[i] < nums[j] and nums[i] < nums[i + 1]:
10+
ans += 1
11+
j = i
12+
return ans

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