Submission #18525894

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Source Code Expand

import sys
input = lambda : sys.stdin.readline().rstrip()
sys.setrecursionlimit(max(1000, 10**9))
write = lambda x: sys.stdout.write(x+"\n")


### 素数の逆元とCombination

M = 10**9+7 # 出力の制限
N = 300 # 必要なテーブルサイズ
g1 = [None] * (N+1) # 元テーブル
g2 = [None] * (N+1) #逆元テーブル
inverse = [None] * (N+1) #逆元テーブル計算用テーブル
g1[0] = g1[1] = g2[0] = g2[1] = 1
inverse[0], inverse[1] = [0, 1] 
for i in range( 2, N + 1 ):
    g1[i] = ( g1[i-1] * i ) % M 
    inverse[i] = ( -inverse[M % i] * (M//i) ) % M # ai+b==0 mod M <=> i==-b*a^(-1) <=> i^(-1)==-b^(-1)*aより
    g2[i] = (g2[i-1] * inverse[i]) % M 
def cmb(n, r, M):
    if ( r<0 or r>n ):
        return 0
    r = min(r, n-r)
    return ((g1[n] * g2[r]) * g2[n-r]) % M
def perm(n, r, M):
    if (r<0 or r>n):
        return 0
    return (g1[n] * g2[n-r]) % M

vs = list(map(int, input().split()))
n = sum(vs)
dp = [0]*(n+1)
dp[0] = 1
s = 0
for v in vs:
    if v==0:
        continue
    ndp = [0]*(n+1)
    for j in range(n+1):
        if dp[j]==0:
            continue
        for a in range(s+1-j+1):
            for b in range(j+1):
                ind = j+v-a-b-b
                ndp[ind] += ((dp[j] * cmb(s+1-j,a,M) % M) * cmb(j,b,M) % M) * cmb(v-1,a+b-1,M)
                ndp[ind] %= M
#                 print(a,b,dp[j] * cmb(s+1-j,a,M) * cmb(j,b,M) * cmb(v-1,a+b-1,M))
    s += v
    dp = ndp
#     print(dp)
ans = dp[0]
print(ans%M)

Submission Info

Judge Result