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/*
Challenge 003
Challenge #2
Create a script that generates Pascal Triangle. Accept number of rows from
the command line. The Pascal Triangle should have at least 3 rows. For more
information about Pascal Triangle, check this wikipedia page.
*/
#include <iostream>
#include <string>
#include <vector>
void draw_pascal(int rows) {
// allocate current and next row
std::vector<int> data[2];
for (int i = 0; i < 2; i++)
data[i].resize(rows+1);
int cur = 0;
data[cur][0] = 1;
for (int row = 1; row <= rows; row++) {
// print current row
for (int col = 0; col < rows-row; col++)
std::cout << ' ';
for (int col = 0; col < row; col++)
std::cout << data[cur][col] << ' ';
std::cout << std::endl;
// compute next row
int nxt = 1-cur;
data[nxt][0] = 1;
data[nxt][row] = 1;
for (int col = 1; col < row; col++)
data[nxt][col] = data[cur][col-1] + data[cur][col];
cur = nxt;
}
}
int main(int argc, char* argv[]) {
if (argc == 2)
draw_pascal(atoi(argv[1]));
}
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