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PascalTriangle.cpp

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// https://www.geeksforgeeks.org/find-the-nth-row-in-pascals-triangle/

#include <iostream>

#include <vector>

template <typename T>

void print(std::vector<T>& items)

{

if (items.size() == 0) {

return;

}

for (auto item : items) {

std::cout << item << " ";

}

std::cout << "\n";

}

std::vector<int> generatePascalTriangleRec(int row)

{

std::vector<int> currentRow;

currentRow.push_back(1);

if (row == 0) {

return currentRow;

}

std::vector<int> previousRow = generatePascalTriangleRec(row - 1);

for (int i = 1; i < previousRow.size(); ++i) {

currentRow.push_back(previousRow[i - 1] + previousRow[i]);

}

currentRow.push_back(1);

return currentRow;

}

std::vector<int> generatePascalTriangleIter(int row)

{

int previous = 1;

std::vector<int> currentRow;

currentRow.push_back(1);

for (int i = 1; i <= row; ++i) {

int current = previous * (row - i + 1) / i;

currentRow.push_back(current);

previous = current;

}

return currentRow;

}

int main()

{

int n = 10;

std::cout << "Recursive\n";

for (int i = 0; i < n; ++i) {

std::cout << "Row " << i << " : ";

std::vector<int> numbers = generatePascalTriangleRec(i);

print(numbers);

}

std::cout << "===============================\n";

std::cout << "Iterative\n";

for (int i = 0; i < n; ++i) {

std::cout << "Row " << i << " : ";

std::vector<int> numbers = generatePascalTriangleIter(i);

print(numbers);

}