hijkl wrote: > this question was asked by Google.. > "Write a program of spiral matrix" > ie. it takes inputs and puts in to matrix as a spiral..example. > given : 3 X 4 matrix > your input in this order : 1 5 8 9 10 7 4 8 0 2 3 6 > will generate following matrix > > 1 5 8 9 > 2 3 6 10 > 0 8 4 7 > > and big O notation for this..
O(k) where k = mn is the number of inputs and the matrix is m x n. Let i0 and i1 be top and bottom rows of the unfilled portion; j0 and j1 are left- and rightmost unfilled columns. Then just walk around the edge of the unfilled space, updating as you go. You're done if there are no unfilled rows or columns left. i0 = j0 = 0; i1 = m - 1; j1 = n - 1; for (;;) { if (i0 > i1) break; for (i = i0++, j = j0; j <= j1; j++) a[i][j] = next_input(); if (j0 > j1) break; for (i = i0, j = j1--; i <= i1; i++) a[i][j] = next_input(); if (i0 > i1) break; for (i = i1--, j = j1; j >= j0; j--) a[i][j] = next_input(); if (j0 > j1) break; for (i = i1, j = j0++; i >= i0; i--) a[i][j] = next_input(); } --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to algogeeks@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups-beta.google.com/group/algogeeks -~----------~----~----~----~------~----~------~--~---