Problème
A standard die produces an integer from 1 through 6. Count all nonempty ordered sequences of outcomes whose sum is target. Different orders count separately. Return the count modulo 1,000,000,007.
Implement dice_combinations(target).
Input
target: The required sum of all rolls.
Output
Return the number of sequences modulo 1,000,000,007.
Contraintes
1 ≤ target ≤ 1,000,000. Taking a count modulo 1,000,000,007 means returning its remainder after division by that number.
Exemples
Entrée :
target = 2
Sortie attendue :
expected = 2Entrée :
long long target = 2;
Sortie attendue :
long long expected = 2;Entrée :
long target = 2;
Sortie attendue :
long expected = 2;Explication
The two sequences are [2] and [1, 1].
Entrée :
target = 4
Sortie attendue :
expected = 8Entrée :
long long target = 4;
Sortie attendue :
long long expected = 8;Entrée :
long target = 4;
Sortie attendue :
long expected = 8;Explication
The sequences are [4], [1,3], [3,1], [2,2], [1,1,2], [1,2,1], [2,1,1], and [1,1,1,1].
Comment l'aborder
Essayez d'abord seul, puis ouvrez les indices un par un.
Indice 1
Think of smaller sums as building blocks for the target.
Indice 2
Use a running count for each sum based on the previous six sums.
Indice 3
Be careful to apply the modulo at every addition and handle sums below 1 separately.
Complexité attendue
O(target) time, O(target) extra space
Références
Ce défi a été adapté pour CodeUtility. Suivez l'énoncé et les contraintes ci-dessus.