Update subarray_sum.cpp

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Swastika Gupta 2021-07-14 14:05:21 +05:30 committed by GitHub
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@ -24,11 +24,11 @@
*/ */
namespace backtracking { namespace backtracking {
/** /**
* @namespace subarraySum * @namespace subarray_sum
* @brief Functions for the [Subset * @brief Functions for the [Subset
* sum](https://en.wikipedia.org/wiki/Subset_sum_problem) implementation * sum](https://en.wikipedia.org/wiki/Subset_sum_problem) implementation
*/ */
namespace subarraySum { namespace subarray_sum {
/** /**
* @brief The main function that implements the count of the subarrays * @brief The main function that implements the count of the subarrays
* @param sum is the required sum of any subarrays * @param sum is the required sum of any subarrays
@ -36,14 +36,14 @@ namespace subarraySum {
* @returns count of the number of subsets with required sum * @returns count of the number of subsets with required sum
*/ */
uint64_t subarray_sum(int sum, const std::vector<int> &in_arr) { uint64_t subarray_sum(int64_t sum, const std::vector<int64_t> &in_arr) {
int nelement = in_arr.size(); int64_t nelement = in_arr.size();
int count_of_subset = 0; int64_t count_of_subset = 0;
int current_sum = 0; int64_t current_sum = 0;
std::unordered_map<int, int> sumarray; // to store the subarrays count std::unordered_map<int64_t, int64_t> sumarray; // to store the subarrays count
// frequency having some sum value // frequency having some sum value
for (int i = 0; i < nelement; i++) { for (int64_t i = 0; i < nelement; i++) {
current_sum += in_arr[i]; current_sum += in_arr[i];
if (current_sum == sum) { if (current_sum == sum) {
@ -57,7 +57,7 @@ uint64_t subarray_sum(int sum, const std::vector<int> &in_arr) {
} }
return count_of_subset; return count_of_subset;
} }
} // namespace subarraySum } // namespace subarray_sum
} // namespace backtracking } // namespace backtracking
/** /**
@ -67,41 +67,41 @@ uint64_t subarray_sum(int sum, const std::vector<int> &in_arr) {
static void test() { static void test() {
// Test 1 // Test 1
std::cout << "1st test "; std::cout << "1st test ";
std::vector<int> array1 = {-7, -3, -2, 5, 8}; // input array std::vector<int64_t> array1 = {-7, -3, -2, 5, 8}; // input array
assert( assert(
backtracking::subarraySum::subarray_sum(0, array1) == backtracking::subarray_sum::subarray_sum(0, array1) ==
1); // first argument in subarray_sum function is the required sum and 1); // first argument in subarray_sum function is the required sum and
// second is the input array, answer is the subarray {(-3,-2,5)} // second is the input array, answer is the subarray {(-3,-2,5)}
std::cout << "passed" << std::endl; std::cout << "passed" << std::endl;
// Test 2 // Test 2
std::cout << "2nd test "; std::cout << "2nd test ";
std::vector<int> array2 = {1, 2, 3, 3}; std::vector<int64_t> array2 = {1, 2, 3, 3};
assert(backtracking::subarraySum::subarray_sum(6, array2) == assert(backtracking::subarray_sum::subarray_sum(6, array2) ==
2); // here we are expecting 2 subsets which sum up to 6 i.e. 2); // here we are expecting 2 subsets which sum up to 6 i.e.
// {(1,2,3),(3,3)} // {(1,2,3),(3,3)}
std::cout << "passed" << std::endl; std::cout << "passed" << std::endl;
// Test 3 // Test 3
std::cout << "3rd test "; std::cout << "3rd test ";
std::vector<int> array3 = {1, 1, 1, 1}; std::vector<int64_t> array3 = {1, 1, 1, 1};
assert(backtracking::subarraySum::subarray_sum(1, array3) == assert(backtracking::subarray_sum::subarray_sum(1, array3) ==
4); // here we are expecting 4 subsets which sum up to 1 i.e. 4); // here we are expecting 4 subsets which sum up to 1 i.e.
// {(1),(1),(1),(1)} // {(1),(1),(1),(1)}
std::cout << "passed" << std::endl; std::cout << "passed" << std::endl;
// Test 4 // Test 4
std::cout << "4th test "; std::cout << "4th test ";
std::vector<int> array4 = {3, 3, 3, 3}; std::vector<int64_t> array4 = {3, 3, 3, 3};
assert(backtracking::subarraySum::subarray_sum(6, array4) == assert(backtracking::subarray_sum::subarray_sum(6, array4) ==
3); // here we are expecting 3 subsets which sum up to 6 i.e. 3); // here we are expecting 3 subsets which sum up to 6 i.e.
// {(3,3),(3,3),(3,3)} // {(3,3),(3,3),(3,3)}
std::cout << "passed" << std::endl; std::cout << "passed" << std::endl;
// Test 5 // Test 5
std::cout << "5th test "; std::cout << "5th test ";
std::vector<int> array5 = {}; std::vector<int64_t> array5 = {};
assert(backtracking::subarraySum::subarray_sum(6, array5) == assert(backtracking::subarray_sum::subarray_sum(6, array5) ==
0); // here we are expecting 0 subsets which sum up to 6 i.e. we 0); // here we are expecting 0 subsets which sum up to 6 i.e. we
// cannot select anything from an empty array // cannot select anything from an empty array
std::cout << "passed" << std::endl; std::cout << "passed" << std::endl;