1.7 KiB
1.7 KiB
id | challengeType | title | forumTopicId |
---|---|---|---|
5900f38b1000cf542c50fe9e | 5 | Problem 31: Coin sums | 301965 |
Description
In England the currency is made up of pound, £, and pence, p, and there are eight coins in general circulation:
1p, 2p, 5p, 10p, 20p, 50p, £1 (100p) and £2 (200p).
It is possible to make £2 in the following way:
1×£1 + 1×50p + 2×20p + 1×5p + 1×2p + 3×1p
How many different ways can n
pence be made using any number of coins?
Instructions
Tests
tests:
- text: <code>coinSums(50)</code> should return a number.
testString: assert(typeof coinSums(50) === 'number');
- text: <code>coinSums(50)</code> should return 451.
testString: assert(coinSums(50) == 451);
- text: <code>coinSums(100)</code> should return 4563.
testString: assert(coinSums(100) == 4563);
- text: <code>coinSums(150)</code> should return 21873.
testString: assert(coinSums(150) == 21873);
- text: <code>coinSums(200)</code> should return 73682.
testString: assert(coinSums(200) == 73682);
Challenge Seed
function coinSums(n) {
return n;
}
coinSums(200);
Solution
const coinSums = (n) => {
const getWays = (n, m=8, c=[1, 2, 5, 10, 20, 50, 100, 200]) => {
if (n === 0) return 1;
if (m === 0 || n < 0) return 0;
return getWays(n - c[m - 1], m, c) + getWays(n, m - 1, c);
};
return getWays(n);
};