Let's see the steps to complete the program.
- Initialise the array.
- Initialise max_sum array of size n.
- Find the max sum for every index and store it in max_sum array.
- Compute the sum of all the elements and store it in a variable sum.
- Write a loop that iterates from i = k to n.
- Add a[i] - a[i - k] to the sum.
- Update the result with max of result, sum.
- Update the result with max of result, sum + max_sum[i - k].
Example
Let's see the code.
#include<bits/stdc++.h>
using namespace std;
int getMaxSum(int a[], int n, int k) {
int maxSum[n];
maxSum[0] = a[0];
int currentMax = a[0];
for (int i = 1; i < n; i++) {
currentMax = max(a[i], currentMax+a[i]);
maxSum[i] = currentMax;
}
int sum = 0;
for (int i = 0; i < k; i++) {
sum += a[i];
}
int result = sum;
for (int i = k; i < n; i++) {
sum += a[i] - a[i-k];
result = max(result, sum);
result = max(result, sum + maxSum[i-k]);
}
return result;
}
int main() {
int a[] = {5, 3, 7, -5, 6, 2, 1};
int k = 6;
cout << getMaxSum(a, 7, k) << endl;
return 0;
}Output
If you run the above code, then you will get the following result.
19
Conclusion
If you have any queries in the tutorial, mention them in the comment section.