Pascal's Triangle II Solutions in C++

// Source : https://oj.leetcode.com/problems/pascals-triangle-ii/
// Author : Hao Chen
// Date   : 2014-06-18



#include <stdlib.h>
#include <vector>
#include <iostream>
using namespace std;

vector<int> getRow(int rowIndex) {
    vector<int> v(rowIndex+1, 0);
    v[0]=1;

    for (int i=0; i<rowIndex; i++){
        for(int j=i+1; j>0; j--){
           v[j] += v[j-1];
        } 
    }
    return v;
    
}

void printVector( vector<int>  pt)
{
    cout << "{ ";
    for(int j=0; j<pt.size(); j++){
        cout << pt[j] << ", ";
    }
    cout << "} " << endl;
}

int main(int argc, char** argv)
{
    int n = 3;
    if (argc>1) {  
        n = atoi(argv[1]);
    }
    printVector(getRow(n)); 
}

#include <vector>
using std::vector; 

class Solution {
public:
    vector<int> getRow(int rowIndex) {
        vector<int> vec(rowIndex+1, 0);
        vec[0] = 1;
        for (int i=0; i<=rowIndex; ++i)
            for (int j=i; j>0; --j)
                vec[j] += vec[j-1];
        return vec;
    }
};

/// Source : https://leetcode.com/problems/pascals-triangle-ii/description/
/// Author : liuyubobobo
/// Time   : 2018-08-10

#include <iostream>
#include <vector>

using namespace std;


/// Simulate Pascal Triangle
///
/// Time Complexity: O(rowIndex^2)
/// Space Complexity: O(rowIndex^2)
class Solution {
public:
    vector<int> getRow(int rowIndex) {
        vector<vector<int>> res(rowIndex + 1, vector<int>(rowIndex + 1, 1));
        for(int i = 2; i <= rowIndex ; i ++)
            for(int j = 1; j < i; j ++ )
                res[i][j] = res[i-1][j-1] + res[i-1][j];
        return res[rowIndex];
    }
};


void print_vec(const vector<int>& vec){
    for(int e: vec)
        cout << e << " ";
    cout << endl;
}

int main() {

    for(int i = 0 ; i < 10 ; i ++)
        print_vec(Solution().getRow(i));

    return 0;
}

/// Source : https://leetcode.com/problems/pascals-triangle-ii/description/
/// Author : liuyubobobo
/// Time   : 2018-08-10

#include <iostream>
#include <vector>

using namespace std;


/// Simulate Pascal Triangle with only O(n) space
///
/// Time Complexity: O(rowIndex^2)
/// Space Complexity: O(rowIndex)
class Solution {
public:
    vector<int> getRow(int rowIndex) {
        vector<vector<int>> res(2, vector<int>(rowIndex + 1, 1));
        for(int i = 2; i <= rowIndex ; i ++)
            for(int j = 1; j < i; j ++ )
                res[i&1][j] = res[(i-1)&1][j-1] + res[(i-1)&1][j];
        return res[rowIndex&1];
    }
};


void print_vec(const vector<int>& vec){
    for(int e: vec)
        cout << e << " ";
    cout << endl;
}

int main() {

    for(int i = 0 ; i < 10 ; i ++)
        print_vec(Solution().getRow(i));

    return 0;
}

/// Source : https://leetcode.com/problems/pascals-triangle-ii/description/
/// Author : liuyubobobo
/// Time   : 2018-08-10

#include <iostream>
#include <vector>

using namespace std;


/// Using Binomial Coefficients
///
/// Time Complexity: O(rowIndex^2)
/// Space Complexity: O(rowIndex)
class Solution {
public:
    vector<int> getRow(int rowIndex) {
        vector<int> res(rowIndex + 1, 1);
        for(int i = 1; i <= (rowIndex + 1) / 2; i ++)
            res[i] = res[rowIndex - i] = C(rowIndex, i);
        return res;
    }

private:
    int C(int m, int n){
        long long up = 1ll;
        int down1 = n, down2 = m - n;
        for(int i = m; i > 0; i --){
            up *= i;
            if(down1 && up % down1 == 0ll) up /= down1, down1 --;
            if(down2 && up % down2 == 0ll) up /= down2, down2 --;
        }
        return up;
    }
};


void print_vec(const vector<int>& vec){
    for(int e: vec)
        cout << e << " ";
    cout << endl;
}

int main() {

    for(int i = 0 ; i < 10 ; i ++)
        print_vec(Solution().getRow(i));

    return 0;
}

/// Source : https://leetcode.com/problems/pascals-triangle-ii/description/
/// Author : liuyubobobo
/// Time   : 2018-08-10

#include <iostream>
#include <vector>

using namespace std;


/// Using Binomial Coefficients Recurrence Relationship
/// Using C(m, n) = (m - n + 1) / n * C(m, n - 1)
///
/// Time Complexity: O(rowIndex)
/// Space Complexity: O(rowIndex)
class Solution {
public:
    vector<int> getRow(int rowIndex) {
        vector<int> res(rowIndex + 1, 1);
        for(int i = 1; i <= (rowIndex + 1) / 2; i ++)
            res[i] = res[rowIndex - i] = (long long)(rowIndex - i + 1) * res[i - 1] / i;
        return res;
    }
};


void print_vec(const vector<int>& vec){
    for(int e: vec)
        cout << e << " ";
    cout << endl;
}

int main() {

    for(int i = 0 ; i < 10 ; i ++)
        print_vec(Solution().getRow(i));

    return 0;
}