||Power indices of weighted majority games are measures of the
effects of parties on the voting in a council.
Among the many kinds of power indices, Banzhaf index, Shapley-Shubik index
and Deegan-Packel index have been studied well.
For computing these power indices, dynamic programming algorithms
had been proposed.
The time complexities of these algorithms are O(n^2q),
O(n^3q), and O(n^4q), respectively.
We propose new algorithms for computing power indices, whose
time complexities are O(nq), O(n^2q), and O(n^2q),