s0007

include/s0007_reverse_integer.hpp

@@ -0,0 +1,12 @@
+#ifndef S0007_REVERSE_INTEGER
+#define S0007_REVERSE_INTEGER
+
+#include <queue>
+#include <cmath>
+
+class Solution {
+public:
+    int reverse(int x);
+};
+
+#endif

src/s0007_reverse_integer.cpp

@@ -0,0 +1,20 @@
+#include "s0007_reverse_integer.hpp"
+
+int Solution::reverse(int x) {
+  int r{0};
+  std::queue<int> queue;
+
+  while (x != 0) {
+    queue.push(x % 10);
+    x = static_cast<int>((x - (x % 10)) / 10);
+  }
+  while (!queue.empty()) {
+    if (r < INT_MIN / 10 || r > INT_MAX / 10) {
+      return 0;
+    }
+    r = r * 10 + queue.front();
+    queue.pop();
+  }
+
+  return r;
+}

tests/s0007_reverse_integer.cpp

@@ -0,0 +1,31 @@
+#include "s0007_reverse_integer.hpp"
+
+#include <gtest/gtest.h>
+
+TEST(Problem7, Case1) {
+  int i = 123;
+  int o = 321;
+  Solution solution;
+  EXPECT_EQ(solution.reverse(i), o);
+}
+
+TEST(Problem7, Case2) {
+  int i = -123;
+  int o = -321;
+  Solution solution;
+  EXPECT_EQ(solution.reverse(i), o);
+}
+
+TEST(Problem7, Case3) {
+  int i = 120;
+  int o = 21;
+  Solution solution;
+  EXPECT_EQ(solution.reverse(i), o);
+}
+
+TEST(Problem7, Case4) {
+  int i = -2147483648;
+  int o = 0;
+  Solution solution;
+  EXPECT_EQ(solution.reverse(i), o);
+}