finding triangulars from array

Question

zero-indexed array A consisting of N integers is given. A triplet (P, Q, R) is triangular if and

A[P] + A[Q] > A[R], 
A[Q] + A[R] > A[P], 
A[R] + A[P         


        

Answer 1

A hint: if you pick just two members of the array then what are the limits on the possible value of the third member of a triangular triplet? Any number outside those limits can be rejected immediately.