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feat: add solutions to lc problem: No.1588. Sum of All Odd Length
Subarrays
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-15
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6 files changed

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‎solution/1500-1599/1588.Sum of All Odd Length Subarrays/README.md

+71-2
Original file line numberDiff line numberDiff line change
@@ -51,27 +51,96 @@
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<li><code>1 &lt;= arr[i] &lt;= 1000</code></li>
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</ul>
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## 解法
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<!-- 这里可写通用的实现逻辑 -->
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“前缀和”实现。
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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 sumOddLengthSubarrays(self, arr: List[int]) -> int:
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n = len(arr)
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presum = [0] * (n + 1)
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for i in range(n):
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presum[i + 1] = presum[i] + arr[i]
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res = 0
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for i in range(n):
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for j in range(0, n, 2):
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if i + j < n:
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res += presum[i + j + 1] - presum[i]
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return res
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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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public int sumOddLengthSubarrays(int[] arr) {
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int n = arr.length;
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int[] presum = new int[n + 1];
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for (int i = 0; i < n; ++i) {
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presum[i + 1] = presum[i] + arr[i];
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}
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int res = 0;
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for (int i = 0; i < n; ++i) {
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for (int j = 0; i + j < n; j += 2) {
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res += presum[i + j + 1] - presum[i];
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}
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}
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return res;
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}
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}
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```
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### **C++**
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```cpp
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class Solution {
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public:
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int sumOddLengthSubarrays(vector<int>& arr) {
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int n = arr.size();
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int presum[n + 1];
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for (int i = 0; i < n; ++i) presum[i + 1] = presum[i] + arr[i];
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int res = 0;
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for (int i = 0; i < n; ++i)
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{
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for (int j = 0; i + j < n; j += 2)
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{
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res += presum[i + j + 1] - presum[i];
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}
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}
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return res;
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}
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};
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```
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### **Go**
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```go
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func sumOddLengthSubarrays(arr []int) int {
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n := len(arr)
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presum := make([]int, n+1)
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for i := range arr {
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presum[i+1] = presum[i] + arr[i]
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}
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res := 0
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for i := 0; i < n; i++ {
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for j := 0; i+j < n; j += 2 {
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res += presum[i+j+1] - presum[i]
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}
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}
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return res
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}
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```
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### **...**

‎solution/1500-1599/1588.Sum of All Odd Length Subarrays/README_EN.md

+69-2
Original file line numberDiff line numberDiff line change
@@ -50,21 +50,88 @@ If we add all these together we get 1 + 4 + 2 + 5 + 3 + 7 + 11 + 10 + 15 = 58</p
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<li><code>1 &lt;= arr[i] &lt;= 1000</code></li>
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</ul>
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53-
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## Solutions
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<!-- tabs:start -->
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### **Python3**
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```python
61-
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class Solution:
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def sumOddLengthSubarrays(self, arr: List[int]) -> int:
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n = len(arr)
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presum = [0] * (n + 1)
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for i in range(n):
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presum[i + 1] = presum[i] + arr[i]
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res = 0
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for i in range(n):
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for j in range(0, n, 2):
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if i + j < n:
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res += presum[i + j + 1] - presum[i]
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return res
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```
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### **Java**
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```java
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class Solution {
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public int sumOddLengthSubarrays(int[] arr) {
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int n = arr.length;
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int[] presum = new int[n + 1];
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for (int i = 0; i < n; ++i) {
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presum[i + 1] = presum[i] + arr[i];
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}
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int res = 0;
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for (int i = 0; i < n; ++i) {
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for (int j = 0; i + j < n; j += 2) {
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res += presum[i + j + 1] - presum[i];
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}
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}
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return res;
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}
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}
94+
```
95+
96+
### **C++**
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```cpp
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class Solution {
100+
public:
101+
int sumOddLengthSubarrays(vector<int>& arr) {
102+
int n = arr.size();
103+
int presum[n + 1];
104+
for (int i = 0; i < n; ++i) presum[i + 1] = presum[i] + arr[i];
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int res = 0;
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for (int i = 0; i < n; ++i)
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{
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for (int j = 0; i + j < n; j += 2)
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{
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res += presum[i + j + 1] - presum[i];
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}
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}
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return res;
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}
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};
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```
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### **Go**
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```go
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func sumOddLengthSubarrays(arr []int) int {
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n := len(arr)
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presum := make([]int, n+1)
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for i := range arr {
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presum[i+1] = presum[i] + arr[i]
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}
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res := 0
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for i := 0; i < n; i++ {
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for j := 0; i+j < n; j += 2 {
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res += presum[i+j+1] - presum[i]
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}
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}
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return res
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}
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```
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### **...**

‎solution/1500-1599/1588.Sum of All Odd Length Subarrays/Solution.cpp

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@@ -0,0 +1,17 @@
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class Solution {
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public:
3+
int sumOddLengthSubarrays(vector<int>& arr) {
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int n = arr.size();
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int presum[n + 1];
6+
for (int i = 0; i < n; ++i) presum[i + 1] = presum[i] + arr[i];
7+
int res = 0;
8+
for (int i = 0; i < n; ++i)
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{
10+
for (int j = 0; i + j < n; j += 2)
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{
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res += presum[i + j + 1] - presum[i];
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}
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}
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return res;
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}
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};

‎solution/1500-1599/1588.Sum of All Odd Length Subarrays/Solution.go

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@@ -0,0 +1,14 @@
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func sumOddLengthSubarrays(arr []int) int {
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n := len(arr)
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presum := make([]int, n+1)
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for i := range arr {
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presum[i+1] = presum[i] + arr[i]
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}
7+
res := 0
8+
for i := 0; i < n; i++ {
9+
for j := 0; i+j < n; j += 2 {
10+
res += presum[i+j+1] - presum[i]
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}
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}
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return res
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}

‎solution/1500-1599/1588.Sum of All Odd Length Subarrays/Solution.java

+9-11
Original file line numberDiff line numberDiff line change
@@ -1,18 +1,16 @@
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class Solution {
22
public int sumOddLengthSubarrays(int[] arr) {
3-
int[] sum = new int[arr.length];
4-
for (int i = 0; i < arr.length; i++) {
5-
sum[i] = (i != 0 ? sum[i - 1] : 0) + arr[i];
3+
int n = arr.length;
4+
int[] presum = new int[n + 1];
5+
for (int i = 0; i < n; ++i) {
6+
presum[i + 1] = presum[i] + arr[i];
67
}
7-
int ans = 0;
8-
// sum[b] - sum[a] 为 (a,b] 的和
9-
for (int i = 0; i < arr.length; i++) {
10-
ans += arr[i];
11-
for (int j = i + 2; j < arr.length; j += 2) {
12-
// [i, j]
13-
ans += sum[j] - sum[i] + arr[i];
8+
int res = 0;
9+
for (int i = 0; i < n; ++i) {
10+
for (int j = 0; i + j < n; j += 2) {
11+
res += presum[i + j + 1] - presum[i];
1412
}
1513
}
16-
return ans;
14+
return res;
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}
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}

‎solution/1500-1599/1588.Sum of All Odd Length Subarrays/Solution.py

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class Solution:
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def sumOddLengthSubarrays(self, arr: List[int]) -> int:
3+
n = len(arr)
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presum = [0] * (n + 1)
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for i in range(n):
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presum[i + 1] = presum[i] + arr[i]
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8+
res = 0
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for i in range(n):
10+
for j in range(0, n, 2):
11+
if i + j < n:
12+
res += presum[i + j + 1] - presum[i]
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return res

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