Project Euler #13 efficiency

Question

Okay, so I finally tackled #13 from Project Euler. I'm said to announce it took me almost 2 hours to come up with this solution, after about an hour of thinking on how to do it.

Here's what I did:

private void Euler13()
{
 // store 50 digit numbers into a 100 by 50 array
 int[,] superMegaInt = { {3,7,1,0,7,2,8,7,5,3,3,9,0,2,1,0,2,7,9,8,7,9,7,9,9,8,2,2,0,8,3,7,5,9,0,2,4,6,5,1,0,1,3,5,7,4,0,2,5,0},
 {4,6,3,7,6,9,3,7,6,7,7,4,9,0,0,0,9,7,1,2,6,4,8,1,2,4,8,9,6,9,7,0,0,7,8,0,5,0,4,1,7,0,1,8,2,6,0,5,3,8},
 {7,4,3,2,4,9,8,6,1,9,9,5,2,4,7,4,1,0,5,9,4,7,4,2,3,3,3,0,9,5,1,3,0,5,8,1,2,3,7,2,6,6,1,7,3,0,9,6,2,9},
 {9,1,9,4,2,2,1,3,3,6,3,5,7,4,1,6,1,5,7,2,5,2,2,4,3,0,5,6,3,3,0,1,8,1,1,0,7,2,4,0,6,1,5,4,9,0,8,2,5,0},
 {2,3,0,6,7,5,8,8,2,0,7,5,3,9,3,4,6,1,7,1,1,7,1,9,8,0,3,1,0,4,2,1,0,4,7,5,1,3,7,7,8,0,6,3,2,4,6,6,7,6},
 {8,9,2,6,1,6,7,0,6,9,6,6,2,3,6,3,3,8,2,0,1,3,6,3,7,8,4,1,8,3,8,3,6,8,4,1,7,8,7,3,4,3,6,1,7,2,6,7,5,7},
 {2,8,1,1,2,8,7,9,8,1,2,8,4,9,9,7,9,4,0,8,0,6,5,4,8,1,9,3,1,5,9,2,6,2,1,6,9,1,2,7,5,8,8,9,8,3,2,7,3,8},
 {4,4,2,7,4,2,2,8,9,1,7,4,3,2,5,2,0,3,2,1,9,2,3,5,8,9,4,2,2,8,7,6,7,9,6,4,8,7,6,7,0,2,7,2,1,8,9,3,1,8},
 {4,7,4,5,1,4,4,5,7,3,6,0,0,1,3,0,6,4,3,9,0,9,1,1,6,7,2,1,6,8,5,6,8,4,4,5,8,8,7,1,1,6,0,3,1,5,3,2,7,6},
 {7,0,3,8,6,4,8,6,1,0,5,8,4,3,0,2,5,4,3,9,9,3,9,6,1,9,8,2,8,9,1,7,5,9,3,6,6,5,6,8,6,7,5,7,9,3,4,9,5,1},
 {6,2,1,7,6,4,5,7,1,4,1,8,5,6,5,6,0,6,2,9,5,0,2,1,5,7,2,2,3,1,9,6,5,8,6,7,5,5,0,7,9,3,2,4,1,9,3,3,3,1},
 {6,4,9,0,6,3,5,2,4,6,2,7,4,1,9,0,4,9,2,9,1,0,1,4,3,2,4,4,5,8,1,3,8,2,2,6,6,3,3,4,7,9,4,4,7,5,8,1,7,8},
 {9,2,5,7,5,8,6,7,7,1,8,3,3,7,2,1,7,6,6,1,9,6,3,7,5,1,5,9,0,5,7,9,2,3,9,7,2,8,2,4,5,5,9,8,8,3,8,4,0,7},
 {5,8,2,0,3,5,6,5,3,2,5,3,5,9,3,9,9,0,0,8,4,0,2,6,3,3,5,6,8,9,4,8,8,3,0,1,8,9,4,5,8,6,2,8,2,2,7,8,2,8},
 {8,0,1,8,1,1,9,9,3,8,4,8,2,6,2,8,2,0,1,4,2,7,8,1,9,4,1,3,9,9,4,0,5,6,7,5,8,7,1,5,1,1,7,0,0,9,4,3,9,0},
 {3,5,3,9,8,6,6,4,3,7,2,8,2,7,1,1,2,6,5,3,8,2,9,9,8,7,2,4,0,7,8,4,4,7,3,0,5,3,1,9,0,1,0,4,2,9,3,5,8,6},
 {8,6,5,1,5,5,0,6,0,0,6,2,9,5,8,6,4,8,6,1,5,3,2,0,7,5,2,7,3,3,7,1,9,5,9,1,9,1,4,2,0,5,1,7,2,5,5,8,2,9},
 {7,1,6,9,3,8,8,8,7,0,7,7,1,5,4,6,6,4,9,9,1,1,5,5,9,3,4,8,7,6,0,3,5,3,2,9,2,1,7,1,4,9,7,0,0,5,6,9,3,8},
 {5,4,3,7,0,0,7,0,5,7,6,8,2,6,6,8,4,6,2,4,6,2,1,4,9,5,6,5,0,0,7,6,4,7,1,7,8,7,2,9,4,4,3,8,3,7,7,6,0,4},
 {5,3,2,8,2,6,5,4,1,0,8,7,5,6,8,2,8,4,4,3,1,9,1,1,9,0,6,3,4,6,9,4,0,3,7,8,5,5,2,1,7,7,7,9,2,9,5,1,4,5},
 {3,6,1,2,3,2,7,2,5,2,5,0,0,0,2,9,6,0,7,1,0,7,5,0,8,2,5,6,3,8,1,5,6,5,6,7,1,0,8,8,5,2,5,8,3,5,0,7,2,1},
 {4,5,8,7,6,5,7,6,1,7,2,4,1,0,9,7,6,4,4,7,3,3,9,1,1,0,6,0,7,2,1,8,2,6,5,2,3,6,8,7,7,2,2,3,6,3,6,0,4,5},
 {1,7,4,2,3,7,0,6,9,0,5,8,5,1,8,6,0,6,6,0,4,4,8,2,0,7,6,2,1,2,0,9,8,1,3,2,8,7,8,6,0,7,3,3,9,6,9,4,1,2},
 {8,1,1,4,2,6,6,0,4,1,8,0,8,6,8,3,0,6,1,9,3,2,8,4,6,0,8,1,1,1,9,1,0,6,1,5,5,6,9,4,0,5,1,2,6,8,9,6,9,2},
 {5,1,9,3,4,3,2,5,4,5,1,7,2,8,3,8,8,6,4,1,9,1,8,0,4,7,0,4,9,2,9,3,2,1,5,0,5,8,6,4,2,5,6,3,0,4,9,4,8,3},
 {6,2,4,6,7,2,2,1,6,4,8,4,3,5,0,7,6,2,0,1,7,2,7,9,1,8,0,3,9,9,4,4,6,9,3,0,0,4,7,3,2,9,5,6,3,4,0,6,9,1},
 {1,5,7,3,2,4,4,4,3,8,6,9,0,8,1,2,5,7,9,4,5,1,4,0,8,9,0,5,7,7,0,6,2,2,9,4,2,9,1,9,7,1,0,7,9,2,8,2,0,9},
 {5,5,0,3,7,6,8,7,5,2,5,6,7,8,7,7,3,0,9,1,8,6,2,5,4,0,7,4,4,9,6,9,8,4,4,5,0,8,3,3,0,3,9,3,6,8,2,1,2,6},
 {1,8,3,3,6,3,8,4,8,2,5,3,3,0,1,5,4,6,8,6,1,9,6,1,2,4,3,4,8,7,6,7,6,8,1,2,9,7,5,3,4,3,7,5,9,4,6,5,1,5},
 {8,0,3,8,6,2,8,7,5,9,2,8,7,8,4,9,0,2,0,1,5,2,1,6,8,5,5,5,4,8,2,8,7,1,7,2,0,1,2,1,9,2,5,7,7,6,6,9,5,4},
 {7,8,1,8,2,8,3,3,7,5,7,9,9,3,1,0,3,6,1,4,7,4,0,3,5,6,8,5,6,4,4,9,0,9,5,5,2,7,0,9,7,8,6,4,7,9,7,5,8,1},
 {1,6,7,2,6,3,2,0,1,0,0,4,3,6,8,9,7,8,4,2,5,5,3,5,3,9,9,2,0,9,3,1,8,3,7,4,4,1,4,9,7,8,0,6,8,6,0,9,8,4},
 {4,8,4,0,3,0,9,8,1,2,9,0,7,7,7,9,1,7,9,9,0,8,8,2,1,8,7,9,5,3,2,7,3,6,4,4,7,5,6,7,5,5,9,0,8,4,8,0,3,0},
 {8,7,0,8,6,9,8,7,5,5,1,3,9,2,7,1,1,8,5,4,5,1,7,0,7,8,5,4,4,1,6,1,8,5,2,4,2,4,3,2,0,6,9,3,1,5,0,3,3,2},
 {5,9,9,5,9,4,0,6,8,9,5,7,5,6,5,3,6,7,8,2,1,0,7,0,7,4,9,2,6,9,6,6,5,3,7,6,7,6,3,2,6,2,3,5,4,4,7,2,1,0},
 {6,9,7,9,3,9,5,0,6,7,9,6,5,2,6,9,4,7,4,2,5,9,7,7,0,9,7,3,9,1,6,6,6,9,3,7,6,3,0,4,2,6,3,3,9,8,7,0,8,5},
 {4,1,0,5,2,6,8,4,7,0,8,2,9,9,0,8,5,2,1,1,3,9,9,4,2,7,3,6,5,7,3,4,1,1,6,1,8,2,7,6,0,3,1,5,0,0,1,2,7,1},
 {6,5,3,7,8,6,0,7,3,6,1,5,0,1,0,8,0,8,5,7,0,0,9,1,4,9,9,3,9,5,1,2,5,5,7,0,2,8,1,9,8,7,4,6,0,0,4,3,7,5},
 {3,5,8,2,9,0,3,5,3,1,7,4,3,4,7,1,7,3,2,6,9,3,2,1,2,3,5,7,8,1,5,4,9,8,2,6,2,9,7,4,2,5,5,2,7,3,7,3,0,7},
 {9,4,9,5,3,7,5,9,7,6,5,1,0,5,3,0,5,9,4,6,9,6,6,0,6,7,6,8,3,1,5,6,5,7,4,3,7,7,1,6,7,4,0,1,8,7,5,2,7,5},
 {8,8,9,0,2,8,0,2,5,7,1,7,3,3,2,2,9,6,1,9,1,7,6,6,6,8,7,1,3,8,1,9,9,3,1,8,1,1,0,4,8,7,7,0,1,9,0,2,7,1},
 {2,5,2,6,7,6,8,0,2,7,6,0,7,8,0,0,3,0,1,3,6,7,8,6,8,0,9,9,2,5,2,5,4,6,3,4,0,1,0,6,1,6,3,2,8,6,6,5,2,6},
 {3,6,2,7,0,2,1,8,5,4,0,4,9,7,7,0,5,5,8,5,6,2,9,9,4,6,5,8,0,6,3,6,2,3,7,9,9,3,1,4,0,7,4,6,2,5,5,9,6,2},
 {2,4,0,7,4,4,8,6,9,0,8,2,3,1,1,7,4,9,7,7,7,9,2,3,6,5,4,6,6,2,5,7,2,4,6,9,2,3,3,2,2,8,1,0,9,1,7,1,4,1},
 {9,1,4,3,0,2,8,8,1,9,7,1,0,3,2,8,8,5,9,7,8,0,6,6,6,9,7,6,0,8,9,2,9,3,8,6,3,8,2,8,5,0,2,5,3,3,3,4,0,3},
 {3,4,4,1,3,0,6,5,5,7,8,0,1,6,1,2,7,8,1,5,9,2,1,8,1,5,0,0,5,5,6,1,8,6,8,8,3,6,4,6,8,4,2,0,0,9,0,4,7,0},
 {2,3,0,5,3,0,8,1,1,7,2,8,1,6,4,3,0,4,8,7,6,2,3,7,9,1,9,6,9,8,4,2,4,8,7,2,5,5,0,3,6,6,3,8,7,8,4,5,8,3},
 {1,1,4,8,7,6,9,6,9,3,2,1,5,4,9,0,2,8,1,0,4,2,4,0,2,0,1,3,8,3,3,5,1,2,4,4,6,2,1,8,1,4,4,1,7,7,3,4,7,0},
 {6,3,7,8,3,2,9,9,4,9,0,6,3,6,2,5,9,6,6,6,4,9,8,5,8,7,6,1,8,2,2,1,2,2,5,2,2,5,5,1,2,4,8,6,7,6,4,5,3,3},
 {6,7,7,2,0,1,8,6,9,7,1,6,9,8,5,4,4,3,1,2,4,1,9,5,7,2,4,0,9,9,1,3,9,5,9,0,0,8,9,5,2,3,1,0,0,5,8,8,2,2},
 {9,5,5,4,8,2,5,5,3,0,0,2,6,3,5,2,0,7,8,1,5,3,2,2,9,6,7,9,6,2,4,9,4,8,1,6,4,1,9,5,3,8,6,8,2,1,8,7,7,4},
 {7,6,0,8,5,3,2,7,1,3,2,2,8,5,7,2,3,1,1,0,4,2,4,8,0,3,4,5,6,1,2,4,8,6,7,6,9,7,0,6,4,5,0,7,9,9,5,2,3,6},
 {3,7,7,7,4,2,4,2,5,3,5,4,1,1,2,9,1,6,8,4,2,7,6,8,6,5,5,3,8,9,2,6,2,0,5,0,2,4,9,1,0,3,2,6,5,7,2,9,6,7},
 {2,3,7,0,1,9,1,3,2,7,5,7,2,5,6,7,5,2,8,5,6,5,3,2,4,8,2,5,8,2,6,5,4,6,3,0,9,2,2,0,7,0,5,8,5,9,6,5,2,2},
 {2,9,7,9,8,8,6,0,2,7,2,2,5,8,3,3,1,9,1,3,1,2,6,3,7,5,1,4,7,3,4,1,9,9,4,8,8,9,5,3,4,7,6,5,7,4,5,5,0,1},
 {1,8,4,9,5,7,0,1,4,5,4,8,7,9,2,8,8,9,8,4,8,5,6,8,2,7,7,2,6,0,7,7,7,1,3,7,2,1,4,0,3,7,9,8,8,7,9,7,1,5},
 {3,8,2,9,8,2,0,3,7,8,3,0,3,1,4,7,3,5,2,7,7,2,1,5,8,0,3,4,8,1,4,4,5,1,3,4,9,1,3,7,3,2,2,6,6,5,1,3,8,1},
 {3,4,8,2,9,5,4,3,8,2,9,1,9,9,9,1,8,1,8,0,2,7,8,9,1,6,5,2,2,4,3,1,0,2,7,3,9,2,2,5,1,1,2,2,8,6,9,5,3,9},
 {4,0,9,5,7,9,5,3,0,6,6,4,0,5,2,3,2,6,3,2,5,3,8,0,4,4,1,0,0,0,5,9,6,5,4,9,3,9,1,5,9,8,7,9,5,9,3,6,3,5},
 {2,9,7,4,6,1,5,2,1,8,5,5,0,2,3,7,1,3,0,7,6,4,2,2,5,5,1,2,1,1,8,3,6,9,3,8,0,3,5,8,0,3,8,8,5,8,4,9,0,3},
 {4,1,6,9,8,1,1,6,2,2,2,0,7,2,9,7,7,1,8,6,1,5,8,2,3,6,6,7,8,4,2,4,6,8,9,1,5,7,9,9,3,5,3,2,9,6,1,9,2,2},
 {6,2,4,6,7,9,5,7,1,9,4,4,0,1,2,6,9,0,4,3,8,7,7,1,0,7,2,7,5,0,4,8,1,0,2,3,9,0,8,9,5,5,2,3,5,9,7,4,5,7},
 {2,3,1,8,9,7,0,6,7,7,2,5,4,7,9,1,5,0,6,1,5,0,5,5,0,4,9,5,3,9,2,2,9,7,9,5,3,0,9,0,1,1,2,9,9,6,7,5,1,9},
 {8,6,1,8,8,0,8,8,2,2,5,8,7,5,3,1,4,5,2,9,5,8,4,0,9,9,2,5,1,2,0,3,8,2,9,0,0,9,4,0,7,7,7,0,7,7,5,6,7,2},
 {1,1,3,0,6,7,3,9,7,0,8,3,0,4,7,2,4,4,8,3,8,1,6,5,3,3,8,7,3,5,0,2,3,4,0,8,4,5,6,4,7,0,5,8,0,7,7,3,0,8},
 {8,2,9,5,9,1,7,4,7,6,7,1,4,0,3,6,3,1,9,8,0,0,8,1,8,7,1,2,9,0,1,1,8,7,5,4,9,1,3,1,0,5,4,7,1,2,6,5,8,1},
 {9,7,6,2,3,3,3,1,0,4,4,8,1,8,3,8,6,2,6,9,5,1,5,4,5,6,3,3,4,9,2,6,3,6,6,5,7,2,8,9,7,5,6,3,4,0,0,5,0,0},
 {4,2,8,4,6,2,8,0,1,8,3,5,1,7,0,7,0,5,2,7,8,3,1,8,3,9,4,2,5,8,8,2,1,4,5,5,2,1,2,2,7,2,5,1,2,5,0,3,2,7},
 {5,5,1,2,1,6,0,3,5,4,6,9,8,1,2,0,0,5,8,1,7,6,2,1,6,5,2,1,2,8,2,7,6,5,2,7,5,1,6,9,1,2,9,6,8,9,7,7,8,9},
 {3,2,2,3,8,1,9,5,7,3,4,3,2,9,3,3,9,9,4,6,4,3,7,5,0,1,9,0,7,8,3,6,9,4,5,7,6,5,8,8,3,3,5,2,3,9,9,8,8,6},
 {7,5,5,0,6,1,6,4,9,6,5,1,8,4,7,7,5,1,8,0,7,3,8,1,6,8,8,3,7,8,6,1,0,9,1,5,2,7,3,5,7,9,2,9,7,0,1,3,3,7},
 {6,2,1,7,7,8,4,2,7,5,2,1,9,2,6,2,3,4,0,1,9,4,2,3,9,9,6,3,9,1,6,8,0,4,4,9,8,3,9,9,3,1,7,3,3,1,2,7,3,1},
 {3,2,9,2,4,1,8,5,7,0,7,1,4,7,3,4,9,5,6,6,9,1,6,6,7,4,6,8,7,6,3,4,6,6,0,9,1,5,0,3,5,9,1,4,6,7,7,5,0,4},
 {9,9,5,1,8,6,7,1,4,3,0,2,3,5,2,1,9,6,2,8,8,9,4,8,9,0,1,0,2,4,2,3,3,2,5,1,1,6,9,1,3,6,1,9,6,2,6,6,2,2},
 {7,3,2,6,7,4,6,0,8,0,0,5,9,1,5,4,7,4,7,1,8,3,0,7,9,8,3,9,2,8,6,8,5,3,5,2,0,6,9,4,6,9,4,4,5,4,0,7,2,4},
 {7,6,8,4,1,8,2,2,5,2,4,6,7,4,4,1,7,1,6,1,5,1,4,0,3,6,4,2,7,9,8,2,2,7,3,3,4,8,0,5,5,5,5,6,2,1,4,8,1,8},
 {9,7,1,4,2,6,1,7,9,1,0,3,4,2,5,9,8,6,4,7,2,0,4,5,1,6,8,9,3,9,8,9,4,2,2,1,7,9,8,2,6,0,8,8,0,7,6,8,5,2},
 {8,7,7,8,3,6,4,6,1,8,2,7,9,9,3,4,6,3,1,3,7,6,7,7,5,4,3,0,7,8,0,9,3,6,3,3,3,3,0,1,8,9,8,2,6,4,2,0,9,0},
 {1,0,8,4,8,8,0,2,5,2,1,6,7,4,6,7,0,8,8,3,2,1,5,1,2,0,1,8,5,8,8,3,5,4,3,2,2,3,8,1,2,8,7,6,9,5,2,7,8,6},
 {7,1,3,2,9,6,1,2,4,7,4,7,8,2,4,6,4,5,3,8,6,3,6,9,9,3,0,0,9,0,4,9,3,1,0,3,6,3,6,1,9,7,6,3,8,7,8,0,3,9},
 {6,2,1,8,4,0,7,3,5,7,2,3,9,9,7,9,4,2,2,3,4,0,6,2,3,5,3,9,3,8,0,8,3,3,9,6,5,1,3,2,7,4,0,8,0,1,1,1,1,6},
 {6,6,6,2,7,8,9,1,9,8,1,4,8,8,0,8,7,7,9,7,9,4,1,8,7,6,8,7,6,1,4,4,2,3,0,0,3,0,9,8,4,4,9,0,8,5,1,4,1,1},
 {6,0,6,6,1,8,2,6,2,9,3,6,8,2,8,3,6,7,6,4,7,4,4,7,7,9,2,3,9,1,8,0,3,3,5,1,1,0,9,8,9,0,6,9,7,9,0,7,1,4},
 {8,5,7,8,6,9,4,4,0,8,9,5,5,2,9,9,0,6,5,3,6,4,0,4,4,7,4,2,5,5,7,6,0,8,3,6,5,9,9,7,6,6,4,5,7,9,5,0,9,6},
 {6,6,0,2,4,3,9,6,4,0,9,9,0,5,3,8,9,6,0,7,1,2,0,1,9,8,2,1,9,9,7,6,0,4,7,5,9,9,4,9,0,1,9,7,2,3,0,2,9,7},
 {6,4,9,1,3,9,8,2,6,8,0,0,3,2,9,7,3,1,5,6,0,3,7,1,2,0,0,4,1,3,7,7,9,0,3,7,8,5,5,6,6,0,8,5,0,8,9,2,5,2},
 {1,6,7,3,0,9,3,9,3,1,9,8,7,2,7,5,0,2,7,5,4,6,8,9,0,6,9,0,3,7,0,7,5,3,9,4,1,3,0,4,2,6,5,2,3,1,5,0,1,1},
 {9,4,8,0,9,3,7,7,2,4,5,0,4,8,7,9,5,1,5,0,9,5,4,1,0,0,9,2,1,6,4,5,8,6,3,7,5,4,7,1,0,5,9,8,4,3,6,7,9,1},
 {7,8,6,3,9,1,6,7,0,2,1,1,8,7,4,9,2,4,3,1,9,9,5,7,0,0,6,4,1,9,1,7,9,6,9,7,7,7,5,9,9,0,2,8,3,0,0,6,9,9},
 {1,5,3,6,8,7,1,3,7,1,1,9,3,6,6,1,4,9,5,2,8,1,1,3,0,5,8,7,6,3,8,0,2,7,8,4,1,0,7,5,4,4,4,9,7,3,3,0,7,8},
 {4,0,7,8,9,9,2,3,1,1,5,5,3,5,5,6,2,5,6,1,1,4,2,3,2,2,4,2,3,2,5,5,0,3,3,6,8,5,4,4,2,4,8,8,9,1,7,3,5,3},
 {4,4,8,8,9,9,1,1,5,0,1,4,4,0,6,4,8,0,2,0,3,6,9,0,6,8,0,6,3,9,6,0,6,7,2,3,2,2,1,9,3,2,0,4,1,4,9,5,3,5},
 {4,1,5,0,3,1,2,8,8,8,0,3,3,9,5,3,6,0,5,3,2,9,9,3,4,0,3,6,8,0,0,6,9,7,7,7,1,0,6,5,0,5,6,6,6,3,1,9,5,4},
 {8,1,2,3,4,8,8,0,6,7,3,2,1,0,1,4,6,7,3,9,0,5,8,5,6,8,5,5,7,9,3,4,5,8,1,4,0,3,6,2,7,8,2,2,7,0,3,2,8,0},
 {8,2,6,1,6,5,7,0,7,7,3,9,4,8,3,2,7,5,9,2,2,3,2,8,4,5,9,4,1,7,0,6,5,2,5,0,9,4,5,1,2,3,2,5,2,3,0,6,0,8},
 {2,2,9,1,8,8,0,2,0,5,8,7,7,7,3,1,9,7,1,9,8,3,9,4,5,0,1,8,0,8,8,8,0,7,2,4,2,9,6,6,1,9,8,0,8,1,1,1,9,7},
 {7,7,1,5,8,5,4,2,5,0,2,0,1,6,5,4,5,0,9,0,4,1,3,2,4,5,8,0,9,7,8,6,8,8,2,7,7,8,9,4,8,7,2,1,8,5,9,6,1,7},
 {7,2,1,0,7,8,3,8,4,3,5,0,6,9,1,8,6,1,5,5,4,3,5,6,6,2,8,8,4,0,6,2,2,5,7,4,7,3,6,9,2,2,8,4,5,0,9,5,1,6},
 {2,0,8,4,9,6,0,3,9,8,0,1,3,4,0,0,1,7,2,3,9,3,0,6,7,1,6,6,6,8,2,3,5,5,5,2,4,5,2,5,2,8,0,4,6,0,9,7,2,2},
 {5,3,5,0,3,5,3,4,2,2,6,4,7,2,5,2,4,2,5,0,8,7,4,0,5,4,0,7,5,5,9,1,7,8,9,7,8,1,2,6,4,3,3,0,3,3,1,6,9,0} };
 label1.Text = AddTheInts(superMegaInt);
}
private string AddTheInts(int[,] ints)
{
 var result = "";
 var total = 0;
 // the idea is to loop through the last element of each array, and add them together, carry the reminder on to the next to the last. repeat till done
 for(var j = 49; j >= 0; j--)
 {
 for (var i = 0; i < 100; i++)
 {
 total += ints[i,j];
 }
 if (j == 0)
 {
 result = total.ToString() + result;
 }
 else
 {
 result = (total % 10).ToString() + result;
 total = total - (total % 10);
 total /= 10;
 }
 }
 return result.Substring(0,10);
}

Now, this works, and I got the correct answer. But I'm 1000% certain there has to be a better way of doing this. And I feel that even if this hadn't taken me 2 hours, if I'd have done this on an interview test, I'd have been laughed at. So, how else should I have accomplished this?

• Jesse C. Slicer: weblogs.asp.net/psteele/archive/2008/12/19/… or maybe geekality.net/2009/10/04/project-euler-problem-13 or even mathblog.dk/project-euler-13
• Justin L.: i hope you didn't write down those arrays manually
• PiousVenom: @JustinL. Not completely.
• Nakilon: The best refactoring here is to take another language: str.scan(/\d{50}/).map(&:to_i).inject(:+).to_s[0...10]
• miracle173: If you have already saved the problem you can create an account at projec euler and submit your solution. Then you are authorized to view the thread for this problem in the restricted project euler forum (the links can be found at tje bottom of the problem 13, but only if you have submitted a valid solution) You acn check the solutions of the other users. Especially the second pos of user rayfil may be interresting if you want to improve your solution: projecteuler.net/thread=13

Answer 1

1. Don't hard code the input. Instead, make your program read and parse a text file containing the input, or something like that.
2. If you can use BigInteger to represent the numbers, use it. If you think that would be cheating, write your own BigInteger that supports Parse(), ToString() and +.
3. You can then use LINQ to sum the numbers. Sum() doesn't work for BigIntegers, but you can use Aggregate().

With that, your code would look something like this:

string result =
 File.ReadAllLines("euler13.txt")
 .Select(BigInteger.Parse)
 .Aggregate((i1, i2) => i1 + i2)
 .ToString()
 .Substring(0, 10);

This is basically the same code as the one from Nakilon's comment, only in a language that supports names with more than 4 characters :-)