ee1e8abd87
* feat(tools): add seed/solution restore script * chore(curriculum): remove empty sections' markers * chore(curriculum): add seed + solution to Chinese * chore: remove old formatter * fix: update getChallenges parse translated challenges separately, without reference to the source * chore(curriculum): add dashedName to English * chore(curriculum): add dashedName to Chinese * refactor: remove unused challenge property 'name' * fix: relax dashedName requirement * fix: stray tag Remove stray `pre` tag from challenge file. Signed-off-by: nhcarrigan <nhcarrigan@gmail.com> Co-authored-by: nhcarrigan <nhcarrigan@gmail.com>
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1.3 KiB
id, title, challengeType, forumTopicId, dashedName
| id | title | challengeType | forumTopicId | dashedName |
|---|---|---|---|---|
| 5900f37b1000cf542c50fe8e | Problem 15: Lattice paths | 5 | 301780 | problem-15-lattice-paths |
--description--
Starting in the top left corner of a 2×2 grid, and only being able to move to the right and down, there are exactly 6 routes to the bottom right corner.
How many such routes are there through a given gridSize?
--hints--
latticePaths(4) should return a number.
assert(typeof latticePaths(4) === 'number');
latticePaths(4) should return 70.
assert.strictEqual(latticePaths(4), 70);
latticePaths(9) should return 48620.
assert.strictEqual(latticePaths(9), 48620);
latticePaths(20) should return 137846528820.
assert.strictEqual(latticePaths(20), 137846528820);
--seed--
--seed-contents--
function latticePaths(gridSize) {
return true;
}
latticePaths(4);
--solutions--
function latticePaths(gridSize) {
let paths = 1;
for (let i = 0; i < gridSize; i++) {
paths *= (2 * gridSize) - i;
paths /= i + 1;
}
return paths;
}