Given an array, find the nearest smaller element G[i] for every element A[i] in the array such that the element has an index smaller than i.
G[i] for an element A[i] = an element A[j] such that j is maximum possible AND j < i AND A[j] < A[i]
Elements for which no smaller element exist, consider next smaller element as -1.
A : [4, 5, 2, 10]
[-1, 4, -1, 2]
A : [3, 2, 1]
[-1, -1, -1]