洛谷 CF743C Vladik and fractions构造一组 x,y,zx,y,zx,y,z,使得对于给定的 nnn,满足: 1x+1y+1z=2n\frac{1}{x}+\frac{1}{y}+\frac{1}{z}=\frac{2}{n}x1+y1+z1=n2