add exercise

Author: charliesbot

cpp/0007_reverse_integer/0007_reverse_integer.h

@@ -0,0 +1,28 @@
+/*
+ * Given a signed 32-bit integer x, return x with its digits reversed.
+ *
+ * If reversing x causes the value to go outside the signed 32-bit integer range
+ * [-231, 231 - 1], then return 0.
+ *
+ * Assume the environment does not allow you to store 64-bit integers (signed or
+ * unsigned).
+ */
+
+#include <cstdlib>
+
+class Solution {
+public:
+  int reverse(int x) {
+    const int negative_helper = x < 0 ? -1 : 1;
+    x = std::abs(x);
+    int result = 0;
+
+    while (x != 0) {
+      const int mod = x % 10;
+      x /= 10;
+      result = result * 10 + mod;
+    }
+
+    return result * negative_helper;
+  }
+};

cpp/0007_reverse_integer/0007_reverse_integer_test.cc

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+#include "0007_reverse_integer.h"
+#include <gtest/gtest.h>
+
+TEST(ReverseInteger, Example1) {
+  const int input = 123;
+  const int output = 321;
+
+  EXPECT_EQ(Solution().reverse(input), output);
+}
+
+TEST(ReverseInteger, Example2) {
+  const int input = -123;
+  const int output = -321;
+
+  EXPECT_EQ(Solution().reverse(input), output);
+}
+
+TEST(ReverseInteger, Example3) {
+  const int input = 120;
+  const int output = 21;
+
+  EXPECT_EQ(Solution().reverse(input), output);
+}
+
+TEST(ReverseInteger, Example4) {
+  const int input = 0;
+  const int output = 0;
+
+  EXPECT_EQ(Solution().reverse(input), output);
+}

typescript/0007_reverse_integer/0007_reverse_integer.test.ts

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+import { reverse } from "./0007_reverse_integer";
+
+test("Reverse Integer 1", () => {
+  const input = 123;
+  const output = 321;
+
+  expect(reverse(input)).toBe(output);
+});
+
+test("Reverse Integer 2", () => {
+  const input = -123;
+  const output = -321;
+
+  expect(reverse(input)).toBe(output);
+});
+
+test("Reverse Integer 3", () => {
+  const input = 120;
+  const output = 21;
+
+  expect(reverse(input)).toBe(output);
+});
+
+test("Reverse Integer 4", () => {
+  const input = 0;
+  const output = 0;
+
+  expect(reverse(input)).toBe(output);
+});

typescript/0007_reverse_integer/0007_reverse_integer.ts

@@ -0,0 +1,24 @@
+/*
+ * Given a signed 32-bit integer x, return x with its digits reversed.
+ *
+ * If reversing x causes the value to go outside the signed 32-bit integer range
+ * [-231, 231 - 1], then return 0.
+ *
+ * Assume the environment does not allow you to store 64-bit integers (signed or unsigned).
+ */
+
+const reverse = (x: number): number => {
+  let negativeHelper = x < 0 ? -1 : 1;
+  let currentNumber = Math.abs(x);
+  let result = 0;
+
+  while (currentNumber > 0) {
+    const mod = currentNumber % 10;
+    currentNumber = Math.floor(currentNumber / 10);
+    result = result * 10 + mod;
+  }
+
+  return result * negativeHelper;
+};
+
+export { reverse };