Project Euler problem 67: find maximum cost path in 100-row triangle

Question

In Project Euler\'s problem 67 there is a triangle given and it contains 100 rows. For e.g.

        5
      9  6
    4   6  8
  0   7  1   5

I.e. 5 + 9 + 6 + 7          


        

Answer 1

#include 
#include 
#include 
#include 

int main() { 
    std::vector > lines;
    lines.resize(100);
    std::ifstream input("triangle.txt");

    for (int i = 0; i < 100; i++) {
        for (int j = 0; j < i + 1; j++) {
            std::string number_string;
            input >> number_string;
            std::istringstream temp(number_string);
            int value = 0;
            temp >> value;
            lines[i].push_back(value);
        }
    } 
    std::vector path1;
    path1.resize(100);
    std::vector path2;
    path2.resize(100);

    for (int i = 0;i < 100;i++) 
        path1[i] = lines[99][i];

    for (int i = 98; i >= 0;i--) {  
        for(int j = 0;j < i+1;j++) {
            if(path1[j] > path1[j + 1]){
                path2[j] = path1[j] + lines[i][j];
            } else{
                path2[j] = path1[j + 1] + lines[i][j];
            }
        }
        for (int i = 0;i < 100;i++) 
            path1[i] = path2[i];
    }
    std::cout << path1[0] << std::endl;
}