Rainbow U

カードの合計枚数と、堀の枚数を与えると、少なくとも1枚堀を持っている確率を返すプログラム
25枚に3枚なら防御率は50%くらいで、4枚だと60％、2枚だと36％。
だから、3枚手にいれよう！というわけではなく、とりあえず、「防御目的のためだけに4枚買うのは無駄っぽい」とだけ覚えておこう。
村系があるとまわりやすいので、マルチプレイでヤバい攻撃カードが多かったら堀3枚くらい買うといいかも。

sum = 25.0
hit = 3.0

def kai(x):
    if x == 0:
       return 1
    else:
       return x * kai(x-1)

bunbo = kai(sum) / kai(sum-5)
bunsi = kai(sum-hit) / kai(sum-hit-5)

answer = 1.0 - bunsi/bunbo
print answer

●ふんばば追記
縦：堀以外の枚数
横：堀の枚数
値：堀を一枚でも持つ確率

	1	2	3	4	5	6	7	8	9	10
0	100%	100%	100%	100%	100%	100%	100%	100%	100%	100%
1	100%	100%	100%	100%	100%	100%	100%	100%	100%	100%
2	100%	100%	100%	100%	100%	100%	100%	100%	100%	100%
3	100%	100%	100%	100%	100%	100%	100%	100%	100%	100%
4	100%	100%	100%	100%	100%	100%	100%	100%	100%	100%
5	83%	95%	98%	99%	100%	100%	100%	100%	100%	100%
6	71%	89%	95%	98%	99%	99%	100%	100%	100%	100%
7	63%	83%	92%	95%	97%	98%	99%	99%	100%	100%
8	56%	78%	88%	93%	96%	97%	98%	99%	99%	99%
9	50%	73%	84%	90%	94%	96%	97%	98%	99%	99%
10	45%	68%	80%	87%	92%	94%	96%	97%	98%	98%
11	42%	64%	77%	85%	89%	93%	95%	96%	97%	98%
12	38%	60%	74%	82%	87%	91%	93%	95%	96%	97%
13	36%	57%	71%	79%	85%	89%	92%	94%	95%	96%
14	33%	54%	68%	77%	83%	87%	90%	92%	94%	95%
15	31%	51%	65%	74%	81%	85%	89%	91%	93%	94%
16	29%	49%	62%	72%	79%	83%	87%	90%	92%	93%
17	28%	47%	60%	70%	77%	82%	85%	88%	91%	92%
18	26%	45%	58%	67%	75%	80%	84%	87%	89%	91%
19	25%	43%	56%	65%	73%	78%	82%	86%	88%	90%
20	24%	41%	54%	64%	71%	76%	81%	84%	87%	89%
21	23%	40%	52%	62%	69%	75%	79%	83%	86%	88%
22	22%	38%	50%	60%	67%	73%	78%	82%	85%	87%
23	21%	37%	49%	58%	66%	72%	76%	80%	83%	86%
24	20%	35%	47%	57%	64%	70%	75%	79%	82%	85%
25	19%	34%	46%	55%	63%	69%	74%	78%	81%	84%
26	19%	33%	45%	54%	61%	67%	72%	76%	80%	83%
27	18%	32%	43%	52%	60%	66%	71%	75%	79%	81%
28	17%	31%	42%	51%	59%	65%	70%	74%	77%	80%
29	17%	30%	41%	50%	57%	63%	68%	73%	76%	79%
30	16%	29%	40%	49%	56%	62%	67%	72%	75%	78%
31	16%	28%	39%	48%	55%	61%	66%	70%	74%	77%
32	15%	28%	38%	47%	54%	60%	65%	69%	73%	76%
33	15%	27%	37%	46%	53%	59%	64%	68%	72%	75%
34	14%	26%	36%	45%	52%	58%	63%	67%	71%	74%
35	14%	26%	35%	44%	51%	57%	62%	66%	70%	73%
36	14%	25%	35%	43%	50%	56%	61%	65%	69%	72%
37	13%	24%	34%	42%	49%	55%	60%	64%	68%	72%
38	13%	24%	33%	41%	48%	54%	59%	63%	67%	71%
39	13%	23%	32%	40%	47%	53%	58%	62%	66%	70%
40	12%	23%	32%	39%	46%	52%	57%	62%	65%	69%
41	12%	22%	31%	39%	45%	51%	56%	61%	65%	68%
42	12%	22%	30%	38%	45%	50%	55%	60%	64%	67%
43	11%	21%	30%	37%	44%	50%	55%	59%	63%	66%
44	11%	21%	29%	37%	43%	49%	54%	58%	62%	66%
45	11%	20%	29%	36%	42%	48%	53%	57%	61%	65%
46	11%	20%	28%	35%	42%	47%	52%	57%	61%	64%
47	10%	20%	28%	35%	41%	47%	51%	56%	60%	63%
48	10%	19%	27%	34%	40%	46%	51%	55%	59%	63%
49	10%	19%	27%	34%	40%	45%	50%	54%	58%	62%
50	10%	18%	26%	33%	39%	45%	49%	54%	58%	61%
51	10%	18%	26%	32%	39%	44%	49%	53%	57%	61%
52	9%	18%	25%	32%	38%	43%	48%	52%	56%	60%
53	9%	18%	25%	31%	37%	43%	47%	52%	56%	59%
54	9%	17%	24%	31%	37%	42%	47%	51%	55%	59%
55	9%	17%	24%	31%	36%	42%	46%	51%	54%	58%
56	9%	17%	24%	30%	36%	41%	46%	50%	54%	57%
57	9%	16%	23%	30%	35%	40%	45%	49%	53%	57%
58	8%	16%	23%	29%	35%	40%	45%	49%	53%	56%
59	8%	16%	23%	29%	34%	39%	44%	48%	52%	55%
60	8%	16%	22%	28%	34%	39%	43%	48%	51%	55%