"At least one" is far easier through the complement: the only way to get none is for every event to fail.

$$P(\text{at least one}) = 1 - \prod_{i=1}^{n}\bigl(1 - P(A_i)\bigr)$$

Return that probability.

solve([0.5, 0.5])        ->  0.75
solve([0.1, 0.1, 0.1])   ->  0.2710000000000001