Intervals (1)

Write a program that, given two intervals, computes the interval corresponding to their intersection, or tells that it is empty.

Input

Input consists of four integer numbers $a_1$ , $b_1$ , $a_2$ , $b_2$ that represent the intervals $[a_1,b_1]$ and $[a_2,b_2]$ . Assume $a_1\le b_1$ and $a_2\le b_2$ .

Output

Print “[]” if their intersection is empty, or “[ $x$ , $y$ ]” if this is their non-empty intersection.

Problem information

Author: Unknown
Translator: Carlos Molina

Generation: 2026-01-25T11:05:15.908Z