Options are wrong I think so...
m$^{(d+1)}$-1 is the ans ...
Height |
No.of keys |
0 |
m-1 |
1 |
m$^1$ * (m-1) |
2 |
m$^2$ * (m-1) |
d |
m$^d$ * (m-1) |
Sum = m-1 + m$^1$* (m-1) + m$^2$ * (m-1) ....+ m$^d$ * (m-1)
= (m-1) ( 1+ m$^2$ + m$^2$ + ... + m$^d$)
= (m-1) [ $\frac{(m^{(d+1)} -1)}{(m-1)}$ ]
= m$^{(d+1)}$ - 1