> a number is divisible by 3 iff the sum of the individual digits is divisible by 3
And how do easily verify this divisibility when "Numeric types, number literals and their associated methods and operations are forbidden?"
And how do easily verify this divisibility when "Numeric types, number literals and their associated methods and operations are forbidden?"
function isDivisibleByThree(num: string): boolean {
let mod3 = "012012012012";
let modulo = "0";
for (const digit of num) {
modulo = mod3[Number(digit) + Number(modulo)];
}
return modulo === "0";
}
"The programmer can use whatever representation they see fit with the only restriction being that it could only contain letters, numbers and symbols that could be typed with a single stroke"
Yeah uh I guess you missed the SUM_TABLE part of the article? That's what they're doing. And that's why the rule against matrices was added.
That version of the code is 80% checking if "the sum of the individual digits is divisible by 3", 20% the rest of the fizzbuzz.
function isDivisibleByThree(num) {
let modulo, mod3 = "012012012012";
for (const digit of num) {
[modulo] = mod3.slice(modulo).slice(digit);
}
return modulo === "0";
}But my real point is they did have the digit sum insight. Their code was already doing your previous suggestion, and if there's a compact way to slice in typescript types it could be adapted to this new method by replacing SUM_TABLE and changing one other line.
The only difference is that they're doing a sum modulo 9 instead of modulo 3, but both of those work fine.