Sum of differences in array

8_kyu/Sum of differences in array/README.md

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+## Sum of differences in array
+
+https://www.codewars.com/kata/5b73fe9fb3d9776fbf00009e
+
+Your task is to sum the differences between consecutive pairs in the array in descending order.
+
+Example
+[2, 1, 10] --> 9
+In descending order: [10, 2, 1]
+
+Sum: (10 - 2) + (2 - 1) = 8 + 1 = 9
+
+If the array is empty or the array has only one element the result should be 0 (Nothing in Haskell, None in Rust).

8_kyu/Sum of differences in array/index.test.ts

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+import { sumOfDifferences } from "./index";
+
+describe("Tests", () => {
+    it("example", () => {
+        expect(sumOfDifferences([1, 2, 10])).toBe(9);
+        expect(sumOfDifferences([-3, -2, -1])).toBe(2);
+    });
+});

8_kyu/Sum of differences in array/index.ts

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+export function sumOfDifferences(arr: number[]): number {
+    arr.sort((a, b) => b - a);
+
+    let sum = 0;
+
+    for (let i = 0; i < arr.length - 1; ++i) {
+        sum += arr[i] - arr[i + 1];
+    }
+
+    return sum;
+}

README.md

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 ### Katas solved
 
-`Total`: 73 \
-`8_kyu`: 56 \
+`Total`: 74 \
+`8_kyu`: 57 \
 `7_kyu`: 13 \
 `6_kyu`: 4 \
 `5_kyu`: 0 \

kata.md

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-8 kyu - Sum of differences in array - https://www.codewars.com/kata/5b73fe9fb3d9776fbf00009e
 8 kyu - Duck Duck Goose - https://www.codewars.com/kata/582e0e592029ea10530009ce
 8 kyu - You only need one - Beginner - https://www.codewars.com/kata/57cc975ed542d3148f00015b
 8 kyu - pick a set of first elements - https://www.codewars.com/kata/572b77262bedd351e9000076