Obtain the Sum solution codechef

Chef is given two integers $N, S$ .

Consider an array $A$ of size $N$ such that $A [i] = i$ for every $1 \leq i \leq N$ .

You are required to find any position $x (1 \leq x \leq N)$ such that :

$(A [1] + A [2] + . . . A [x - 1]) + (A [x + 1] + A [x + 2] + . . . A [N]) = S$

If there are multiple such positions $x$ , print any such position. If there is no such position, print $- 1$ .

For each testcase, output the required position or $- 1$ in case there is no such position.

2
5
-1

Test Case $1$ : $A [1] + A [3] + A [4] = 1 + 3 + 4 = 8$ , so $x = 2$ is a suitable position.

Test Case $3$ : There is no suitable position.

Obtain the Sum solution codechef- Chef is given two integers N,SN,S. Consider an array AA of size NN such that A[i]=iA[i]=i for every 1≤i≤N1≤i≤N. You are required to find any position x(1≤x≤N)x(1≤x≤N) such that :