how to calculate an index and vice versa
- To: mathgroup at smc.vnet.net
- Subject: [mg119277] how to calculate an index and vice versa
- From: ferradini <gianmarco.ferradini at email.it>
- Date: Sat, 28 May 2011 07:20:12 -0400 (EDT)
given n numbers (eg. 1 to 90) I can build the following list of numbers k (in this case 4) 1, 2, 3, 4 associated index -> 0 1, 2, 3, 5 associated index -> 1 1, 2, 3, 6 associated index -> 2 1, 2, 3, 7 associated index -> 3 1, 2, 3, 8 ................... .... 1, 2, 3, 9 ....................... ....................... ....................... 10, 41, 60, 61 associated index -> 954722 ....................... ....................... 87, 88, 89, 90 associated index -> 2555190 I need to build an algorithm to assign eg 4 elemnti can obtain its index in the list (1, 2, 3, 7 return 3) The second algorithm is 'inverse: given a number such as 954722 I get the four elements 87; 88, 89, 90. The elemnti in the list are always sorted values. I thank those who will send me information on the subject to follow Thank ferradini