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[Med] Bracket Match Generation (programming.dev)

submitted 1 year ago* (last edited 1 year ago) by Ategon@programming.dev to c/challenges@programming.dev

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Bracket Inc. wants to ship out new products using their excess brackets. They have tasked you with generating every possible assortment of brackets for some n brackets where the brackets will match

A bracket match is an opening and closing version of the same kind of bracket beside each other ()
If a bracket matches then outer brackets can also match (())
n will be an even number
The valid brackets are ()[]{}

For example for n = 4 the options are

()()
(())
[][]
[[]]
{}{}
{{}}
[]()
()[]
(){}
{}()
[]{}
{}[]
({})
{()}
([])
[()]
{[]}
[{}]

You must accept n as a command line argument (entered when your app is ran) and print out all of the matches, one per line

(It will be called like node main.js 4 or however else to run apps in your language)

You can use the solution tester in this post to test you followed the correct format https://programming.dev/post/1805174

Any programming language may be used. 2 points will be given if you pass all the test cases with 1 bonus point going to whoevers performs the quickest and 1 for whoever can get the least amount of characters

To submit put the code and the language you used below

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[–] brie 1 points 1 year ago

Probably doesn't count since the lines are out of order, but here's a first attempt at a C solution.

#include <stdio.h>

char const brackets[6] = "()[]{}";

void combo(int pairs, int seed)
{
	if (pairs <= 0) {
		return;
	}
	char const *pair = brackets + ((seed % 3) << 1);
	if (pairs == 1) {
		putchar(pair[0]);
		putchar(pair[1]);
	} else {
		putchar(pair[0]);
		if (seed & 1) {
			combo(pairs - 1, seed / 6);
			putchar(pair[1]);
		} else {
			putchar(pair[1]);
			combo(pairs - 1, seed / 6);
		}
	}
}

int main(int argc, char **argv)
{
	int n;
	size_t combos = 1;
	size_t i;

	sscanf(argv[1], "%d", &n);
	for (i = 0; i < n; i += 2) {
		combos *= 6;
	}
	combos >>= 1;
	int pairs = n / 2;
	for (i = 0; i < combos; i++) {
		combo(pairs, i);
		puts("");
	}
	return 0;
}