1.7 KiB
1.7 KiB
id | title | challengeType | forumTopicId | dashedName |
---|---|---|---|---|
59713bd26bdeb8a594fb9413 | Count the coins | 5 | 302238 | count-the-coins |
--description--
There are four types of common coins in US currency:
- quarters (25 cents)
- dimes (10 cents)
- nickels (5 cents), and
- pennies (1 cent)
There are six ways to make change for 15 cents:
- A dime and a nickel
- A dime and 5 pennies
- 3 nickels
- 2 nickels and 5 pennies
- A nickel and 10 pennies
- 15 pennies
--instructions--
Implement a function to determine how many ways there are to make change for a given input, cents
, that represents an amount of US pennies using these common coins.
--hints--
countCoins
should be a function.
assert(typeof countCoins === 'function');
countCoins(15)
should return 6
.
assert.equal(countCoins(15), 6);
countCoins(85)
shouls return 163
.
assert.equal(countCoins(85), 163);
countCoins(100)
should return 242
.
assert.equal(countCoins(100), 242);
--seed--
--seed-contents--
function countCoins(cents) {
return true;
}
--solutions--
function countCoins(cents) {
const operands = [1, 5, 10, 25];
const targetsLength = cents + 1;
const operandsLength = operands.length;
const t = [1];
for (let a = 0; a < operandsLength; a++) {
for (let b = 1; b < targetsLength; b++) {
// initialise undefined target
t[b] = t[b] ? t[b] : 0;
// accumulate target + operand ways
t[b] += (b < operands[a]) ? 0 : t[b - operands[a]];
}
}
return t[targetsLength - 1];
}