Solve InterviewCake's top-scores problem

Write a function to sort a list of scores for a game in linear time. While I had
previously solved this in python, I hadn't marked the todo.org file, so I ended
up doing this again.

"Perfect practice makes perfect."

scratch/deepmind/part_two/todo.org

@@ -18,7 +18,7 @@
 * Sorting, searching, and logarithms
 ** DONE Find Rotation Point
 ** TODO Find Repeat, Space Edition
-** TODO Top Scores
+** DONE Top Scores
 ** TODO Merging Meeting Times
 * Trees and graphs
 ** TODO Balanced Binary Tree

scratch/deepmind/part_two/top-scores.ts

@@ -0,0 +1,58 @@
+function sortScores(xs: Array<number>, highest: number): Array<number> {
+  const counts: Array<number> = [];
+  const result: Array<number> = [];
+
+  // Initialize counts
+  for (let i = 0; i <= highest; i += 1) {
+    counts.push(0);
+  }
+
+  for (let i = 0; i < xs.length; i += 1) {
+    counts[xs[i]] += 1
+  }
+
+  for (let i = highest; i >= 0; i -= 1) {
+    let count: number = counts[i];
+
+    for (let j = 0; j < count; j += 1) {
+      result.push(i);
+    }
+  }
+
+  return result;
+}
+
+
+// Tests
+let desc = 'no scores';
+let actual = sortScores([], 100);
+let expected = [];
+assertEqual(JSON.stringify(actual), JSON.stringify(expected), desc);
+
+desc = 'one score';
+actual = sortScores([55], 100);
+expected = [55];
+assertEqual(JSON.stringify(actual), JSON.stringify(expected), desc);
+
+desc = 'two scores';
+actual = sortScores([30, 60], 100);
+expected = [60, 30];
+assertEqual(JSON.stringify(actual), JSON.stringify(expected), desc);
+
+desc = 'many scores';
+actual = sortScores([37, 89, 41, 65, 91, 53], 100);
+expected = [91, 89, 65, 53, 41, 37];
+assertEqual(JSON.stringify(actual), JSON.stringify(expected), desc);
+
+desc = 'repeated scores';
+actual = sortScores([20, 10, 30, 30, 10, 20], 100);
+expected = [30, 30, 20, 20, 10, 10];
+assertEqual(JSON.stringify(actual), JSON.stringify(expected), desc);
+
+function assertEqual(a, b, desc) {
+  if (a === b) {
+    console.log(`${desc} ... PASS`);
+  } else {
+    console.log(`${desc} ... FAIL: ${a} != ${b}`);
+  }
+}