feat: Add House Robber algorithm (TheAlgorithms#1524)

* Create house_robber.cpp * updating DIRECTORY.md * Update dynamic_programming/house_robber.cpp Co-authored-by: Abhinn Mishra <[email protected]> * Update dynamic_programming/house_robber.cpp Co-authored-by: Abhinn Mishra <[email protected]> * Update dynamic_programming/house_robber.cpp Co-authored-by: Abhinn Mishra <[email protected]> * clang-format and clang-tidy fixes for c00823e * Update house_robber.cpp * clang-format and clang-tidy fixes for cdf701c * Update house_robber.cpp * clang-format and clang-tidy fixes for 39c3719 * Update dynamic_programming/house_robber.cpp Co-authored-by: Abhinn Mishra <[email protected]> * clang-format and clang-tidy fixes for 126e3f2 * Update house_robber.cpp * Update dynamic_programming/house_robber.cpp Co-authored-by: David Leal <[email protected]> * Update dynamic_programming/house_robber.cpp Co-authored-by: David Leal <[email protected]> * Update dynamic_programming/house_robber.cpp Co-authored-by: David Leal <[email protected]> * Update dynamic_programming/house_robber.cpp Co-authored-by: David Leal <[email protected]> * Update house_robber.cpp * clang-format and clang-tidy fixes for 474a5f0 * Update dynamic_programming/house_robber.cpp Co-authored-by: David Leal <[email protected]> * Update dynamic_programming/house_robber.cpp Co-authored-by: David Leal <[email protected]> * clang-format and clang-tidy fixes for 203cce3 * Update house_robber.cpp * Update house_robber.cpp * Update house_robber.cpp * clang-format and clang-tidy fixes for 6b0bea9 * Apply suggestions from code review * Apply suggestions from code review * clang-format and clang-tidy fixes for 913baf8 Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com> Co-authored-by: Abhinn Mishra <[email protected]> Co-authored-by: David Leal <[email protected]>
shiv-tyagi · Jul 9, 2021 · 6115bc2 · 6115bc2
1 parent 1ab5e4e
commit 6115bc2
Show file tree

Hide file tree

Showing 2 changed files with 115 additions and 0 deletions.
diff --git a/DIRECTORY.md b/DIRECTORY.md
@@ -74,6 +74,7 @@
   * [Egg Dropping Puzzle](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/dynamic_programming/egg_dropping_puzzle.cpp)
   * [Fibonacci Bottom Up](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/dynamic_programming/fibonacci_bottom_up.cpp)
   * [Floyd Warshall](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/dynamic_programming/floyd_warshall.cpp)
+  * [House Robber](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/dynamic_programming/house_robber.cpp)
   * [Kadane](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/dynamic_programming/kadane.cpp)
   * [Kadane2](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/dynamic_programming/kadane2.cpp)
   * [Longest Common String](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/dynamic_programming/longest_common_string.cpp)

diff --git a/dynamic_programming/house_robber.cpp b/dynamic_programming/house_robber.cpp
@@ -0,0 +1,114 @@
+/**
+ * @file
+ * @brief Implementation of [House Robber
+ * Problem](https://labuladong.gitbook.io/algo-en/i.-dynamic-programming/houserobber)
+ * algorithm
+ * @details
+ * Solution of House robber problem uses a dynamic programming concept that
+ * works in \f$O(n)\f$ time and works in \f$O(1)\f$ space.
+ * @author [Swastika Gupta](https://github.com/Swastyy)
+ */
+
+#include <cassert>   /// for assert
+#include <climits>   /// for std::max
+#include <iostream>  /// for io operations
+#include <vector>    /// for std::vector
+
+/**
+ * @namespace dynamic_programming
+ * @brief Dynamic Programming algorithms
+ */
+namespace dynamic_programming {
+/**
+ * @namespace house_robber
+ * @brief Functions for the [House
+ * Robber](https://labuladong.gitbook.io/algo-en/i.-dynamic-programming/houserobber)
+ * algorithm
+ */
+namespace house_robber {
+/**
+ * @brief The main function that implements the House Robber algorithm using
+ * dynamic programming
+ * @param money array containing money in the ith house
+ * @param n size of array
+ * @returns maximum amount of money that can be robbed
+ */
+std::uint32_t houseRobber(const std::vector<uint32_t> &money,
+                          const uint32_t &n) {
+    if (n == 0) {  // if there is no house
+        return 0;
+    }
+    if (n == 1) {  // if there is only one house
+        return money[0];
+    }
+    if (n == 2) {  // if there are two houses, one with the maximum amount of
+                   // money will be robbed
+        return std::max(money[0], money[1]);
+    }
+    uint32_t max_value = 0;  // contains maximum stolen value at the end
+    uint32_t value1 = money[0];
+    uint32_t value2 = std::max(money[0], money[1]);
+    for (uint32_t i = 2; i < n; i++) {
+        max_value = std::max(money[i] + value1, value2);
+        value1 = value2;
+        value2 = max_value;
+    }
+
+    return max_value;
+}
+}  // namespace house_robber
+}  // namespace dynamic_programming
+
+/**
+ * @brief Self-test implementations
+ * @returns void
+ */
+static void test() {
+    // Test 1
+    // [1, 2, 3, 1] return 4
+    std::vector<uint32_t> array1 = {1, 2, 3, 1};
+    std::cout << "Test 1... ";
+    assert(
+        dynamic_programming::house_robber::houseRobber(array1, array1.size()) ==
+        4);  // here the two non-adjacent houses that are robbed are first and
+             // third with total sum money as 4
+    std::cout << "passed" << std::endl;
+
+    // Test 2
+    // [6, 7, 1, 3, 8, 2, 4] return 19
+    std::vector<uint32_t> array2 = {6, 7, 1, 3, 8, 2, 4};
+    std::cout << "Test 2... ";
+    assert(
+        dynamic_programming::house_robber::houseRobber(array2, array2.size()) ==
+        19);  // here the four non-adjacent houses that are robbed are first,
+              // third, fifth and seventh with total sum money as 19
+    std::cout << "passed" << std::endl;
+
+    // Test 3
+    // [] return 0
+    std::vector<uint32_t> array3 = {};
+    std::cout << "Test 3... ";
+    assert(
+        dynamic_programming::house_robber::houseRobber(array3, array3.size()) ==
+        0);  // since there is no house no money can be robbed
+    std::cout << "passed" << std::endl;
+
+    // Test 4
+    // [2,7,9,3,1] return 12
+    std::vector<uint32_t> array4 = {2, 7, 9, 3, 1};
+    std::cout << "Test 4... ";
+    assert(
+        dynamic_programming::house_robber::houseRobber(array4, array4.size()) ==
+        12);  // here the three non-adjacent houses that are robbed are first,
+              // third and fifth with total sum money as 12
+    std::cout << "passed" << std::endl;
+}
+
+/**
+ * @brief Main function
+ * @returns 0 on exit
+ */
+int main() {
+    test();  // run self-test implementations
+    return 0;
+}