|
| 1 | +/** |
| 2 | + * @file |
| 3 | + * @brief Implementation of [House Robber |
| 4 | + * Problem](https://labuladong.gitbook.io/algo-en/i.-dynamic-programming/houserobber) |
| 5 | + * algorithm |
| 6 | + * @details |
| 7 | + * Solution of House robber problem uses a dynamic programming concept that |
| 8 | + * works in \f$O(n)\f$ time and works in \f$O(1)\f$ space. |
| 9 | + * @author [Swastika Gupta](https://github.com/Swastyy) |
| 10 | + */ |
| 11 | + |
| 12 | +#include <cassert> /// for assert |
| 13 | +#include <climits> /// for std::max |
| 14 | +#include <iostream> /// for io operations |
| 15 | +#include <vector> /// for std::vector |
| 16 | + |
| 17 | +/** |
| 18 | + * @namespace dynamic_programming |
| 19 | + * @brief Dynamic Programming algorithms |
| 20 | + */ |
| 21 | +namespace dynamic_programming { |
| 22 | +/** |
| 23 | + * @namespace house_robber |
| 24 | + * @brief Functions for the [House |
| 25 | + * Robber](https://labuladong.gitbook.io/algo-en/i.-dynamic-programming/houserobber) |
| 26 | + * algorithm |
| 27 | + */ |
| 28 | +namespace house_robber { |
| 29 | +/** |
| 30 | + * @brief The main function that implements the House Robber algorithm using |
| 31 | + * dynamic programming |
| 32 | + * @param money array containing money in the ith house |
| 33 | + * @param n size of array |
| 34 | + * @returns maximum amount of money that can be robbed |
| 35 | + */ |
| 36 | +std::uint32_t houseRobber(const std::vector<uint32_t> &money, |
| 37 | + const uint32_t &n) { |
| 38 | + if (n == 0) { // if there is no house |
| 39 | + return 0; |
| 40 | + } |
| 41 | + if (n == 1) { // if there is only one house |
| 42 | + return money[0]; |
| 43 | + } |
| 44 | + if (n == 2) { // if there are two houses, one with the maximum amount of |
| 45 | + // money will be robbed |
| 46 | + return std::max(money[0], money[1]); |
| 47 | + } |
| 48 | + uint32_t max_value = 0; // contains maximum stolen value at the end |
| 49 | + uint32_t value1 = money[0]; |
| 50 | + uint32_t value2 = std::max(money[0], money[1]); |
| 51 | + for (uint32_t i = 2; i < n; i++) { |
| 52 | + max_value = std::max(money[i] + value1, value2); |
| 53 | + value1 = value2; |
| 54 | + value2 = max_value; |
| 55 | + } |
| 56 | + |
| 57 | + return max_value; |
| 58 | +} |
| 59 | +} // namespace house_robber |
| 60 | +} // namespace dynamic_programming |
| 61 | + |
| 62 | +/** |
| 63 | + * @brief Self-test implementations |
| 64 | + * @returns void |
| 65 | + */ |
| 66 | +static void test() { |
| 67 | + // Test 1 |
| 68 | + // [1, 2, 3, 1] return 4 |
| 69 | + std::vector<uint32_t> array1 = {1, 2, 3, 1}; |
| 70 | + std::cout << "Test 1... "; |
| 71 | + assert( |
| 72 | + dynamic_programming::house_robber::houseRobber(array1, array1.size()) == |
| 73 | + 4); // here the two non-adjacent houses that are robbed are first and |
| 74 | + // third with total sum money as 4 |
| 75 | + std::cout << "passed" << std::endl; |
| 76 | + |
| 77 | + // Test 2 |
| 78 | + // [6, 7, 1, 3, 8, 2, 4] return 19 |
| 79 | + std::vector<uint32_t> array2 = {6, 7, 1, 3, 8, 2, 4}; |
| 80 | + std::cout << "Test 2... "; |
| 81 | + assert( |
| 82 | + dynamic_programming::house_robber::houseRobber(array2, array2.size()) == |
| 83 | + 19); // here the four non-adjacent houses that are robbed are first, |
| 84 | + // third, fifth and seventh with total sum money as 19 |
| 85 | + std::cout << "passed" << std::endl; |
| 86 | + |
| 87 | + // Test 3 |
| 88 | + // [] return 0 |
| 89 | + std::vector<uint32_t> array3 = {}; |
| 90 | + std::cout << "Test 3... "; |
| 91 | + assert( |
| 92 | + dynamic_programming::house_robber::houseRobber(array3, array3.size()) == |
| 93 | + 0); // since there is no house no money can be robbed |
| 94 | + std::cout << "passed" << std::endl; |
| 95 | + |
| 96 | + // Test 4 |
| 97 | + // [2,7,9,3,1] return 12 |
| 98 | + std::vector<uint32_t> array4 = {2, 7, 9, 3, 1}; |
| 99 | + std::cout << "Test 4... "; |
| 100 | + assert( |
| 101 | + dynamic_programming::house_robber::houseRobber(array4, array4.size()) == |
| 102 | + 12); // here the three non-adjacent houses that are robbed are first, |
| 103 | + // third and fifth with total sum money as 12 |
| 104 | + std::cout << "passed" << std::endl; |
| 105 | +} |
| 106 | + |
| 107 | +/** |
| 108 | + * @brief Main function |
| 109 | + * @returns 0 on exit |
| 110 | + */ |
| 111 | +int main() { |
| 112 | + test(); // run self-test implementations |
| 113 | + return 0; |
| 114 | +} |
0 commit comments