Added inner outer method

README.md

@@ -19,10 +19,11 @@ It contains all the logic needed to manage tournaments.
 
 - Number of participants : 8, 16, 32, etc. (powers of two)
 - Optional Consolation Final : matches semi-final losers.
-- Handles up to 3 first places.
+- Handles up to 4 first places.
 
 ## Double elimination
 
+- Twice the number of matches.
 - Contains a Winner Bracket (WB) and a Loser Bracket (LB).
 - Number of participants : 8, 16, 32, etc. (powers of two)
 - Optional Grand Final : matches the WB winner against the LB winner.
@@ -34,7 +35,7 @@ It contains all the logic needed to manage tournaments.
 - This library doesn't come with a GUI to create and update tournaments. You need to create your own.
 - You can use [brackets-viewer.js](https://github.com/Drarig29/brackets-viewer.js) to display the current state of a stage.
 - It is designed to be used with any storage.
-- An example of JSON storage is given to run tests, but you can use it out of the box.
+- An example of JSON storage is given to run tests. You can use it out of the box.
 - It uses asynchronous calls to a storage interface to be able to handle asynchronous SQL requests.
 
 # Credits

src/helpers.ts

@@ -15,4 +15,36 @@ export function makeViewer(data: TournamentData) {
 </script>`;
 
     fs.writeFileSync('viewer/viewer.html', html);
+}
+
+/**
+ * Toornament's method to distribute seeds in the first round of single or double elimination.
+ */
+export function innerOuterMethod(array: number[]): number[][] {
+    const size = array.length / 4;
+    const parts = {
+        inner: [array.slice(size, 2 * size), array.slice(2 * size, 3 * size)],
+        outer: [array.slice(0, size), array.slice(3 * size, 4 * size)]
+    }
+
+    function inner(part: number[][]): number[] {
+        return [part[0].pop()!, part[1].shift()!];
+    }
+
+    function outer(part: number[][]): number[] {
+        return [part[0].shift()!, part[1].pop()!];
+    }
+
+    const result: number[][] = [];
+
+    for (let i = 0; i < size / 2; i++) {
+        result.push(
+            outer(parts.outer), // Outer's outer
+            inner(parts.inner), // Inner's inner
+            inner(parts.outer), // Outer's inner
+            outer(parts.inner), // Inner's outer
+        );
+    }
+
+    return result;
 }

test/helpers.spec.js

@@ -0,0 +1,30 @@
+const assert = require('chai').assert;
+const { innerOuterMethod } = require('../dist/helpers');
+
+describe('Test participants placement', () => {
+    it('should place 8 participants with inner-outer method', () => {
+        const teams = [1, 2, 3, 4, 5, 6, 7, 8];
+        const placement = innerOuterMethod(teams);
+        assert.deepEqual(placement, [
+            [1, 8],
+            [4, 5],
+            [2, 7],
+            [3, 6],
+        ]);
+    });
+
+    it('should place 16 participants with inner-outer method', () => {
+        const teams = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16];
+        const placement = innerOuterMethod(teams);
+        assert.deepEqual(placement, [
+            [1, 16],
+            [8, 9],
+            [4, 13],
+            [5, 12],
+            [2, 15],
+            [7, 10],
+            [3, 14],
+            [6, 11],
+        ]);
+    });
+});