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feat: add Strassen's Matrix Multiplication (#2413)

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* Feat: Add Strassen's matrix multiplication

* updating DIRECTORY.md

* Fix cpp lint error

* updating DIRECTORY.md

* clang-format and clang-tidy fixes for 02439b57

* Fix windows error

* Add namespaces

* updating DIRECTORY.md

* Proper documentation

* Reduce the matrix size.

* updating DIRECTORY.md

* clang-format and clang-tidy fixes for 0545555a

Co-authored-by: toastedbreadandomelette <toastedbreadandomelette@gmail.com>
Co-authored-by: github-actions[bot] <github-actions@users.noreply.github.com>
Co-authored-by: David Leal <halfpacho@gmail.com>
This commit is contained in:
Ashish Bhanu Daulatabad
2023-01-25 01:33:06 +05:30
committed by GitHub
parent a6a9d8e75a
commit 5b238724b8
6 changed files with 745 additions and 241 deletions
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48
dynamic_programming/subset_sum.cpp
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@@ -5,19 +5,19 @@
* whether a subset with target sum exists or not.
*
* @details
* In this problem, we use dynamic programming to find if we can pull out a
* subset from an array whose sum is equal to a given target sum. The overall
* time complexity of the problem is O(n * targetSum) where n is the size of
* the array. For example, array = [1, -10, 2, 31, -6], targetSum = -14.
* Output: true => We can pick subset [-10, 2, -6] with sum as
* In this problem, we use dynamic programming to find if we can pull out a
* subset from an array whose sum is equal to a given target sum. The overall
* time complexity of the problem is O(n * targetSum) where n is the size of
* the array. For example, array = [1, -10, 2, 31, -6], targetSum = -14.
* Output: true => We can pick subset [-10, 2, -6] with sum as
* (-10) + 2 + (-6) = -14.
* @author [KillerAV](https://github.com/KillerAV)
*/
#include <cassert> /// for std::assert
#include <iostream> /// for IO operations
#include <vector> /// for std::vector
#include <unordered_map> /// for unordered map
#include <unordered_map> /// for unordered map
#include <vector> /// for std::vector
/**
* @namespace dynamic_programming
@@ -33,33 +33,31 @@ namespace dynamic_programming {
namespace subset_sum {
/**
* Recursive function using dynamic programming to find if the required sum
* Recursive function using dynamic programming to find if the required sum
* subset exists or not.
* @param arr input array
* @param targetSum the target sum of the subset
* @param dp the map storing the results
* @returns true/false based on if the target sum subset exists or not.
*/
bool subset_sum_recursion(
const std::vector<int> &arr,
int targetSum,
std::vector<std::unordered_map<int, bool>> *dp,
int index = 0) {
if(targetSum == 0) { // Found a valid subset with required sum.
bool subset_sum_recursion(const std::vector<int> &arr, int targetSum,
std::vector<std::unordered_map<int, bool>> *dp,
int index = 0) {
if (targetSum == 0) { // Found a valid subset with required sum.
return true;
}
if(index == arr.size()) { // End of array
if (index == arr.size()) { // End of array
return false;
}
if ((*dp)[index].count(targetSum)) { // Answer already present in map
if ((*dp)[index].count(targetSum)) { // Answer already present in map
return (*dp)[index][targetSum];
}
bool ans = subset_sum_recursion(arr, targetSum - arr[index], dp, index + 1)
|| subset_sum_recursion(arr, targetSum, dp, index + 1);
(*dp)[index][targetSum] = ans; // Save ans in dp map.
bool ans =
subset_sum_recursion(arr, targetSum - arr[index], dp, index + 1) ||
subset_sum_recursion(arr, targetSum, dp, index + 1);
(*dp)[index][targetSum] = ans; // Save ans in dp map.
return ans;
}
@@ -84,10 +82,10 @@ bool subset_sum_problem(const std::vector<int> &arr, const int targetSum) {
static void test() {
// custom input vector
std::vector<std::vector<int>> custom_input_arr(3);
custom_input_arr[0] = std::vector<int> {1, -10, 2, 31, -6};
custom_input_arr[1] = std::vector<int> {2, 3, 4};
custom_input_arr[2] = std::vector<int> {0, 1, 0, 1, 0};
custom_input_arr[0] = std::vector<int>{1, -10, 2, 31, -6};
custom_input_arr[1] = std::vector<int>{2, 3, 4};
custom_input_arr[2] = std::vector<int>{0, 1, 0, 1, 0};
std::vector<int> custom_input_target_sum(3);
custom_input_target_sum[0] = -14;
custom_input_target_sum[1] = 10;