OJ-Problems-Source/HDOJ/4248_autoAC.cpp
2016-09-04 15:25:29 +08:00

49 lines
1.6 KiB
C++

#include <cstdio>
#include <cstring>
typedef long long Long;
const int MOD = 1000000007;
int C[11111][111];
void init() {
C[0][0] = C[1][0] = C[1][1] = 1;
for (int i = 2; i <= 10101; i++) {
for (int j = 0; j <= i && j <= 100; j++) {
if (j == 0) C[i][j] = 1;
else C[i][j] = (C[i - 1][j] + C[i - 1][j - 1]) % MOD;
}
}
}
int dp[111][11111];
int a[111];
int main() {
init();
for (int ii = 1;;ii++) {
int n; if (scanf("%d",&n) == -1) break;
memset(dp,0,sizeof(dp));
memset(a,0,sizeof(a));
for (int i = 0; i < n; i++) {
scanf("%d",a + i);
}
for (int i = 0; i <= a[0]; i++) dp[0][i] = 1;
int maxlen = a[0];
for (int now = 0; now < n - 1; now ++) {
int next = now + 1;
for (int len = 0; len <= maxlen; len++) {
if (dp[now][len] == 0) continue;
dp[next][len] += dp[now][len];
if (dp[next][len] >= MOD) dp[next][len] -= MOD;
Long tmp = dp[now][len];
for (int put = 1; put <= a[next]; put++) {
Long tt = tmp * C[len + put][put] % MOD;
dp[next][len + put] += tt;
if (dp[next][len + put] >= MOD) dp[next][len + put] -= MOD;
}
}
maxlen += a[next];
}
int ans = 0;
for (int i = 1; i <= maxlen; i++) ans = (ans + dp[n - 1][i]) % MOD;
printf("Case %d: %d\n",ii,ans);
}
return 0;
}