概率树
设置成功概率和深度，查看每个分支的组合概率。
SSS
SSF
SFS
SFF
FSS
FSF
FFS
FFF
S → S → S12.50%
S → S → F12.50%
S → F → S12.50%
S → F → F12.50%
F → S → S12.50%
F → S → F12.50%
F → F → S12.50%
F → F → F12.50%
按成功次数计算的概率(不分顺序)
恰好0次成功12.50%
恰好1次成功37.50%
恰好2次成功37.50%
恰好3次成功12.50%
