diff --git a/greedy_algorithms/jump_game.cpp b/greedy_algorithms/jump_game.cpp new file mode 100644 index 00000000000..4bf126bc783 --- /dev/null +++ b/greedy_algorithms/jump_game.cpp @@ -0,0 +1,74 @@ +/** + * @file + * @brief [Jumping Game](https://leetcode.com/problems/jump-game/) + * algorithm implementation + * @details + * + * Given an array of non-negative integers, you are initially positioned at the + * first index of the array. Each element in the array represents your maximum + * jump length at that position. Determine if you are able to reach the last + * index. This solution takes in input as a vector and output as a boolean to + * check if you can reach the last position. We name the indices good and bad + * based on whether we can reach the destination if we start at that position. + * We initialize the last index as lastPos. + * Here, we start from the end of the array and check if we can ever reach the + * first index. We check if the sum of the index and the maximum jump count + * given is greater than or equal to the lastPos. If yes, then that is the last + * position you can reach starting from the back. After the end of the loop, if + * we reach the lastPos as 0, then the destination can be reached from the start + * position. + * + * @author [Rakshaa Viswanathan](https://github.com/rakshaa2000) + * @author [David Leal](https://github.com/Panquesito7) + */ + +#include /// for assert +#include /// for std::cout +#include /// for std::vector + +/** + * @namespace + * @brief Greedy Algorithms + */ +namespace greedy_algorithms { +/** + * @brief Checks whether the given element (default is `1`) can jump to the last + * index. + * @param nums array of numbers containing the maximum jump (in steps) from that + * index + * @returns true if the index can be reached + * @returns false if the index can NOT be reached + */ +bool can_jump(const std::vector &nums) { + size_t lastPos = nums.size() - 1; + for (size_t i = lastPos; i != static_cast(-1); i--) { + if (i + nums[i] >= lastPos) { + lastPos = i; + } + } + return lastPos == 0; +} +} // namespace greedy_algorithms + +/** + * @brief Function to test the above algorithm + * @returns void + */ +static void test() { + assert(greedy_algorithms::can_jump(std::vector({4, 3, 1, 0, 5}))); + assert(!greedy_algorithms::can_jump(std::vector({3, 2, 1, 0, 4}))); + assert(greedy_algorithms::can_jump(std::vector({5, 9, 4, 7, 15, 3}))); + assert(!greedy_algorithms::can_jump(std::vector({1, 0, 5, 8, 12}))); + assert(greedy_algorithms::can_jump(std::vector({2, 1, 4, 7}))); + + std::cout << "All tests have successfully passed!\n"; +} + +/** + * @brief Main function + * @returns 0 on exit + */ +int main() { + test(); // run self-test implementations + return 0; +} diff --git a/greedy_algorithms/jumpgame.cpp b/greedy_algorithms/jumpgame.cpp deleted file mode 100644 index 8a890319154..00000000000 --- a/greedy_algorithms/jumpgame.cpp +++ /dev/null @@ -1,68 +0,0 @@ -/** - * @file - * @brief Implementation of an algorithm to solve the [jumping game]((https://leetcode.com/problems/jump-game/)) problem - * @details - * **Problem statement:** Given an array of non-negative integers, you are initially positioned at the first index of the array. Each element in the array represents your maximum jump length at that position. Determine if you are able to reach the last index. - * This solution takes in input as a vector and output as a boolean to check if you can reach the last position. - * We name the indices good and bad based on whether we can reach the destination if we start at that position. - * We initialize the last index as lastPos. - * Here, we start from the end of the array and check if we can ever reach the first index. - * We check if the sum of the index and the maximum jump count given is greater than or equal to the lastPos. - * If yes, then that is the last position you can reach starting from the back. - * After the end of the loop, if we reach the lastPos as 0, then the destination can be reached from the start position. - * @author [Rakshaa Viswanathan](https://github.com/rakshaa2000) -*/ - -#include -#include -#include - - - /** - * @brief This function implements the above algorithm - * @param array of numbers containing the maximum jump (in steps) from that index - * @returns bool value whether final index can be reached or not - */ -bool canJump(const std::vector &nums) { - auto lastPos = nums.size() - 1; - for (auto i = nums.size() - 1; i >= 0; i--) { - if (i + nums[i] >= lastPos) { - lastPos = i; - } - } - return lastPos == 0; -} - - -/** - * @brief Function to test above algorithm - * @returns void - */ -static void test(){ - // Test 1 - std::vector num1={4,3,1,0,5}; - assert(canJump(num1)==true); - std::cout<<"Input: "; - for(auto i: num1){ - std::cout< num2={3,2,1,0,4}; - assert(canJump(num2)==false); - std::cout<<"Input: "; - for(auto i: num2){ - std::cout<