67 lines
1.5 KiB
C++
67 lines
1.5 KiB
C++
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#include <bits/stdc++.h>
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using namespace std;
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const int MOD = 998244353;
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#ifdef DEBUG
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#define PRINT_VALUE(v){cout<<#v<<" :"<<v<<endl;}
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#define PRINT_ARRAY(arr,size){cout<<#arr<<" [";for(int i=1;i<=size;i++){cout<<arr[i]<<(i!=size?",":"]\n");}}
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#define DEBUG_PRINT(c){cout<<c<<endl;}
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#endif
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#ifndef DEBUG
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#define PRINT_VALUE(v)
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#define PRINT_ARRAY(arr,size)
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#define DEBUG_PRINT(c)
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#endif
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int main() {
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int n, m;
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cin >> n >> m;
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vector<int> lim(n);
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for (int i = 0; i < n; ++i) {
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cin >> lim[i];
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}
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vector<vector<int>> dp(n + 1, vector<int>(m + 1, 0));
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dp[0][0] = 1;
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vector<int> positions;
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for (int i = 1; i <= n; ++i) {
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if (lim[i - 1] == 0) {
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positions.push_back(i);
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}
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}
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int total_permutations = 1;
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for (int i = 1; i <= positions.size(); ++i) {
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total_permutations = (total_permutations * i) % MOD;
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}
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for (int i = 1; i <= n; ++i) {
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if (lim[i - 1] != 0) {
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for (int j = 0; j <= m; ++j) {
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dp[i][j] = dp[i - 1][j];
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}
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} else {
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for (int j = 0; j <= m; ++j) {
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for (int k = 0; k < i; ++k) {
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if (j - k >= 0) {
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dp[i][j] = (dp[i][j] + dp[i - 1][j - k]) % MOD;
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}
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}
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}
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}
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}
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int result = 0;
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for (int j = 0; j <= m; ++j) {
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result = (result + dp[n][j]) % MOD;
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}
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result = (result * total_permutations) % MOD;
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cout << result << endl;
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return 0;
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}
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