Project Euler Problem 85
解法
Σ[0<=x
実装(Ruby)
def solve(w,h) w*(w+1)*h*(h+1)/4 end p solve(3,2) x=1 ans=1 max=4000000 target=2000000 loop do break if solve(x,x)>target+(target-ans).abs for y in x..1000000 if (target-solve(x,y)).abs<(target-ans).abs ans=solve(x,y) p x*y end break if solve(x,y)>target+(target-ans).abs end x+=1 end