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