"""Tests for lis.py."""
import unittest
import random
from lis import lis_length, lis, lis_indices, is_increasing


class TestLIS(unittest.TestCase):
    def test_empty(self):
        self.assertEqual(lis_length([]), 0)
        self.assertEqual(lis([]), [])
        self.assertEqual(lis_indices([]), [])

    def test_single(self):
        self.assertEqual(lis_length([5]), 1)
        self.assertEqual(lis([5]), [5])

    def test_sorted(self):
        self.assertEqual(lis_length([1,2,3,4]), 4)
        self.assertEqual(lis([1,2,3,4]), [1,2,3,4])

    def test_reverse(self):
        self.assertEqual(lis_length([4,3,2,1]), 1)

    def test_duplicates_strict(self):
        self.assertEqual(lis_length([1,1,1]), 1)
        self.assertEqual(lis([2,2,1,1,3]), [1,3])

    def test_known(self):
        seq = [10, 9, 2, 5, 3, 7, 101, 18]
        self.assertEqual(lis_length(seq), 4)
        sub = lis(seq)
        self.assertEqual(len(sub), 4)
        self.assertTrue(is_increasing(sub))

    def test_indices(self):
        seq = [3, 1, 2]
        idx = lis_indices(seq)
        self.assertEqual([seq[i] for i in idx], lis(seq))
        self.assertEqual(lis_length(seq), 2)

    def test_brute_random(self):
        def brute(seq):
            n = len(seq)
            if n == 0:
                return 0
            dp = [1]*n
            for i in range(n):
                for j in range(i):
                    if seq[j] < seq[i]:
                        dp[i] = max(dp[i], dp[j]+1)
            return max(dp)
        rng = random.Random(42)
        for _ in range(300):
            L = rng.randint(0, 14)
            seq = [rng.randint(-6, 6) for _ in range(L)]
            self.assertEqual(lis_length(seq), brute(seq))
            sub = lis(seq)
            self.assertEqual(len(sub), brute(seq))
            self.assertTrue(is_increasing(sub))
            idx = lis_indices(seq)
            self.assertEqual([seq[i] for i in idx], sub)

    def test_tuple_input(self):
        self.assertEqual(lis_length((3,1,4,1,5)), 3)
        sub = lis((3,1,4,1,5))
        self.assertEqual(len(sub), 3)
        self.assertTrue(is_increasing(sub))


if __name__ == "__main__":
    unittest.main()