11. Largest product in a grid

1. 개요

문제는 이곳에서 확인할 수 있다. 어떤 숫자더미에서 상하좌우 및 대각선 방향으로 숫자 4개를 곱하여 가장 큰 값을 구하는 것이 목표이다.

2. Ver 1.0

인덱스를 맞추는 것은 귀찮은 일이므로 상하좌우 및 대각선 방향으로 4개의 숫자를 찾되 IndexOutOfRangeException이 발생하면 바로 다음의 경우를 찾는 식으로 구현한다.

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69

using System; using System.Collections.Generic; using System.Linq;   class ProjectEuler {     static void Main(string[] args)     {         string str_data = @"08 02 22 97 38 15 00 40 00 75 04 05 07 78 52 12 50 77 91 08                             49 49 99 40 17 81 18 57 60 87 17 40 98 43 69 48 04 56 62 00                             81 49 31 73 55 79 14 29 93 71 40 67 53 88 30 03 49 13 36 65                             52 70 95 23 04 60 11 42 69 24 68 56 01 32 56 71 37 02 36 91                             22 31 16 71 51 67 63 89 41 92 36 54 22 40 40 28 66 33 13 80                             24 47 32 60 99 03 45 02 44 75 33 53 78 36 84 20 35 17 12 50                             32 98 81 28 64 23 67 10 26 38 40 67 59 54 70 66 18 38 64 70                             67 26 20 68 02 62 12 20 95 63 94 39 63 08 40 91 66 49 94 21                             24 55 58 05 66 73 99 26 97 17 78 78 96 83 14 88 34 89 63 72                             21 36 23 09 75 00 76 44 20 45 35 14 00 61 33 97 34 31 33 95                             78 17 53 28 22 75 31 67 15 94 03 80 04 62 16 14 09 53 56 92                             16 39 05 42 96 35 31 47 55 58 88 24 00 17 54 24 36 29 85 57                             86 56 00 48 35 71 89 07 05 44 44 37 44 60 21 58 51 54 17 58                             19 80 81 68 05 94 47 69 28 73 92 13 86 52 17 77 04 89 55 40                             04 52 08 83 97 35 99 16 07 97 57 32 16 26 26 79 33 27 98 66                             88 36 68 87 57 62 20 72 03 46 33 67 46 55 12 32 63 93 53 69                             04 42 16 73 38 25 39 11 24 94 72 18 08 46 29 32 40 62 76 36                             20 69 36 41 72 30 23 88 34 62 99 69 82 67 59 85 74 04 36 16                             20 73 35 29 78 31 90 01 74 31 49 71 48 86 81 16 23 57 05 54                             01 70 54 71 83 51 54 69 16 92 33 48 61 43 52 01 89 19 67 48";                   List<List<int>> data = new List<List<int>>();                   foreach(string row in str_data.Split('\r'))         {             data.Add(new List<int>());             foreach( string n in row.Trim().Split(' '))             {                 data[data.Count-1].Add(Convert.ToInt16(n));             }         }                   int max_prod = 0;                   foreach(var idx in new[]{new{r=0,c=1}, new{r=1,c=1},                                  new{r=1,c=0}, new{r=1,c=-1}})         {             for(int i=0; i<data.Count; i++)             {                 for(int j=0; j<data[0].Count; j++)                 {                     int prod = 1;                                           try                     {                         for(int k=0; k<4; k++)                         {                             prod *= data[i+idx.r*k][j+idx.c*k];                         }                                                   if(max_prod < prod)                         {                             max_prod = prod;                         }                     } catch {}                 }             }         }         Console.WriteLine(max_prod);     } }

답은 70600674이다.