# Cracking the coding interview: Equilibrium Point — 8

Given an array A of n positive numbers. The task is to find the first Equilibium Point in the array.

Equilibrium Point in an array is a position such that the sum of elements before it is equal to the sum of elements after it.

**Note: Retun the index of Equilibrium point. (1-based index)**

**Example 1:**

**Input: **

n = 5

A[] = {1,3,5,2,2}

**Output: **3** **

Explanation: For second test case

equilibrium point is at position 3

as elements before it (1+3) =

elements after it (2+2).

**Example 2:**

**Input:**

n = 1

A[] = {1}

**Output: **1

Explanation:

Since its the only element hence

its the only equilibrium point.

**Your Task:**

The task is to complete the function **equilibriumPoint()** which takes the array and n as input parameters and returns the point of equilibrium. Return -1 if no such point exists.

**Expected Time Complexity: **O(n)**Expected Auxiliary Space:** O(1)

**Constraints:**

1 <= n <= 106

1 <= A[i] <= 108

Solution:

Time complexity: O(n)

Space complexity: O(1)