Gaykutan.R

gyakutan.R

# http://blog.goo.ne.jp/r-de-r/e/c9cc759642ea0c02560bd08c975fb156

b = 0.111111 * 1:9 # b は 0.111111 ～ 0.999999 の 9 種類
bz = b+0.000001
b2 = 2 * b
bz2 = 2*bz
b.sq = b ^ 2
bz.sq = bz ^ 2
n = 10000 # 探索範囲上限
ansa = c()
for (a in 1:n) {
  x = a * b2 + b.sq
  xz = a * bz2 + bz.sq
  pp = floor(xz) - floor(x) - (xz == round(xz))
  if (any(pp > 0)) {
    ans = (a+b[which(pp>0)])^2
    ansa = c(ansa, ans)
  }
}