解法为：x^2-(y+1)^2=(x+y+1)(x-y-1)
x^2 -(y+1)^2=(x+y+1)(x-y-1)
X^2-Y^2-2Y-1=x^2-(y^2+2y+1)=x^2-(y+1)^2=(x+y+1)(x-y-1)
x^2-(y+1)^2=(x+y+1)(x-y-1)
（x+y)(x-y)-(2y+1)
