Data Structure Array: Maximum sum such that no two elements are adjacent

http://www.geeksforgeeks.org/maximum-sum-such-that-no-two-elements-are-adjacent/

 1 #include <iostream>
 2 #include <vector>
 3 #include <algorithm>
 4 #include <queue>
 5 #include <stack>
 6 #include <string>
 7 #include <fstream>
 8 #include <map>
 9 using namespace std;
10 
11 int maxsum(int arr[], int n) {
12     int insum = arr[0];
13     int exsum = 0;
14     for (int i = 1; i < n; i++) {
15         int tmp = max(insum, exsum);
16         insum = exsum + arr[i];
17         exsum = tmp;
18     }
19     return max(insum, exsum);
20 }
21 
22 int main() {
23     int arr[6] = {5, 5, 10, 100, 10, 5};
24     cout << maxsum(arr, 6) << endl;
25     return 0;
26 }