Find Indices of Soldiers for Reconnaissance Unit in C++

Suppose we have an array A with n elements. There are n soldiers standing on a circle. For ith soldier, the height is A[i]. A reconnaissance unit can be made of such two adjacent soldiers, whose heights difference is minimal. So each of them will be less noticeable with the other. We have to find the indices of the pair of soldiers that can form a reconnaissance unit.

So, if the input is like A = [10, 12, 13, 15, 10], then the output will be (5, 1).

Steps

To solve this, we will follow these steps −

n := size of A
D := |A[0] - A[n - 1]|
H := n
for initialize i := 1, when i < n, update (increase i by 1), do:
   if D > |A[i] - A[i - 1]|, then:
      D := |A[i] - A[i - 1]|
      H := i
print H and (H mod n)

Example

Let us see the following implementation to get better understanding −

#include <bits/stdc++.h>
using namespace std;

void solve(vector<int> A) {
   int n = A.size();
   int D = abs(A[0] - A[n - 1]);
   int H = n;
   for (int i = 1; i < n; i++) {
      if (D > abs(A[i] - A[i - 1])) {
         D = abs(A[i] - A[i - 1]);
         H = i;
      }
   }
   cout << H << ", " << (H % n) + 1;
}
int main() {
   vector<int> A = { 10, 12, 13, 15, 10 };
   solve(A);
}

Input

{ 10, 12, 13, 15, 10 }

Output

5, 1