Poker Straight

1. Problem Description

LL is in a great mood today because he bought a deck of playing cards and found that it contains 2 big jokers and 2 small jokers (a deck originally has 54 cards ^_^)… He randomly draws 5 cards to test his luck and see whether he can get a straight. If he does, he plans to buy a lottery ticket. “Ace of hearts, 3 of spades, small joker, big joker, 5 of diamonds” — “Oh My God!” It is not a straight… LL is unhappy, so he decides that the big and small jokers can represent any number, with A treated as 1, J as 11, Q as 12, and K as 13. The five cards above can then become “1,2,3,4,5” (the jokers are treated as 2 and 4), “So Lucky!”. Now simulate this process and determine LL’s luck. Output true if the cards can form a straight; otherwise output false. For convenience, treat the jokers as 0.

2. Approach

3. Implementation

import "sort"


// Time complexity: O(NlogN)
// Space complexity: O(1)
func IsContinuous(numbers []int) bool {
	if len(numbers) == 0 {
		return false
	}

	sort.Ints(numbers)
	notZero := 0
	for notZero = 0; notZero < len(numbers); notZero++ {
		if numbers[notZero] != 0 {
			break
		}
	}

	diff := 0
	for i := notZero; i < len(numbers)-1; i++ {
		res := numbers[i+1] - numbers[i]
		if res == 0 {
			return false

		}
		diff += res
	}

	return diff < len(numbers)
}

4. References

• Straight in Poker - NowCoder