Problème
Convert a valid Roman numeral to its value. Symbols are I=1, V=5, X=10, L=50, C=100, D=500, M=1000; a smaller symbol before a larger one is subtracted (IV = 4, CM = 900).
Implement roman_to_int(text).
Input
text: A valid Roman numeral.
Output
Return its value.
Contraintes
1 ≤ value ≤ 3,999
Exemples
Exemple 1
Entrée :
text = "XIV"
Sortie attendue :
expected = 14Entrée :
std::string text = "XIV";
Sortie attendue :
long long expected = 14;Entrée :
string text = "XIV";
Sortie attendue :
long expected = 14;Explication
X = 10, IV = 4: 14.
Exemple 2
Entrée :
text = "MCMXCIV"
Sortie attendue :
expected = 1994Entrée :
std::string text = "MCMXCIV";
Sortie attendue :
long long expected = 1994;Entrée :
string text = "MCMXCIV";
Sortie attendue :
long expected = 1994;Explication
M=1000, CM=900, XC=90, IV=4: 1994.
Comment l'aborder
Essayez d'abord seul, puis ouvrez les indices un par un.
Indice 1
Most symbols add their value, but some pairs subtract when a smaller symbol appears before a larger one.
Indice 2
Process the numeral from left to right and compare each symbol with the next one.
Indice 3
Make sure the last symbol is always handled correctly since it has no follower.
Complexité attendue
O(n) time, O(1) extra space
Références
Ce défi a été adapté pour CodeUtility. Suivez l'énoncé et les contraintes ci-dessus.