# Project Euler-Problem 38

November 1, 2011
By

(This article was first published on YGC » R, and kindly contributed to R-bloggers)

Take the number 192 and multiply it by each of 1, 2, and 3:

192 × 1 = 192
192 × 2 = 384
192 × 3 = 576

By concatenating each product we get the 1 to 9 pandigital, 192384576. We will call 192384576 the concatenated product of 192 and (1,2,3)

The same can be achieved by starting with 9 and multiplying by 1, 2, 3, 4, and 5, giving the pandigital, 918273645, which is the concatenated product of 9 and (1,2,3,4,5).

What is the largest 1 to 9 pandigital 9-digit number that can be formed as the concatenated product of an integer with (1,2, ... , n) where n > 1?


?View Code RSPLUS
 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21  maxP <- 1 for (i in 1:9999) { p <- i for (j in 2:9) { product <- i * j p <- paste(p, product, sep="") if (nchar(p)== 9) { tmp <- unlist(strsplit(p, split="")) if (any(tmp == "0")) break if (length(unique(tmp)) == length(tmp)) { if ( p > maxP) { maxP <- p cat (i ,"\t", j ,"\t", p, "\n") } } } else if (nchar(p) > 9) { break } } }