#include <cstdio> #include <vector> using namespace std; int n; unsigned int p = 1000000007; vector<int> a; typedef struct { int val; int num; } node; vector<node> b; const int max_val = 5001; const int max_n = 5001; void print_b() { for(unsigned int i = 0; i < b.size(); ++i) { printf("%d - %d\n", b[i].val, b[i].num); } } unsigned int newt[max_n][max_n]; unsigned long long s[max_val * max_n]; unsigned long long s2[max_val * max_n]; int lasts; void calc_newt() { for(int i = 1; i < max_n; ++i) { newt[i][0] = 1; newt[i][i] = 1; } for(int i = 2; i < max_n; ++i) { for(int j = 1; j < i; ++j) { newt[i][j] = (newt[i-1][j-1] + newt[i-1][j]) % p; } } } void print_s() { for(int i = 1; i <= lasts; ++i) { if (s[i] > 0) { printf(" (%d - %llu)", i, s[i]); } } printf("\n"); } void clean_s2(int a, int b) { for(int i = a; i <=b; ++i) { s2[i] = 0; } } unsigned long long calc_s() { unsigned long long result = 0; for(int x = 1; x <= b[0].num; ++x) { s[x] = newt[b[0].num][x]; } lasts = b[0].num; for(auto it = b.begin()+1; it != b.end(); ++it) { int val = it->val; int num = it->num; clean_s2(val+val-1, lasts); for(int x = 1; x <= num; ++x) { unsigned int count = newt[num][x]; unsigned int sum = val*x; for(int i = val-1; i <= lasts; ++i) { s2[sum+i] = (s2[sum+i] + (s[i]*count % p)) % p; } } for(int i = val+val-1; i <= val*num+lasts; ++i) { s[i] = (s[i] + s2[i]) % p; } lasts = val*num+lasts; // print_s(); } for(int i = 1; i <= lasts; ++i) { result = (result + s[i]) % p; } return result; } int main() { scanf("%d", &n); a.resize(max_val); for(int i = 0; i < n; ++i) { int x; scanf("%d", &x); a[x]++; } for(int i = 1; i < max_val; ++i) { node nd; if (a[i] > 0) { nd.val = i; nd.num = a[i]; b.push_back(nd); } } if (b[0].val != 1) { printf("0\n"); return 0; } calc_newt(); printf("%llu\n", calc_s()); //print_s(); return 0; }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 | #include <cstdio> #include <vector> using namespace std; int n; unsigned int p = 1000000007; vector<int> a; typedef struct { int val; int num; } node; vector<node> b; const int max_val = 5001; const int max_n = 5001; void print_b() { for(unsigned int i = 0; i < b.size(); ++i) { printf("%d - %d\n", b[i].val, b[i].num); } } unsigned int newt[max_n][max_n]; unsigned long long s[max_val * max_n]; unsigned long long s2[max_val * max_n]; int lasts; void calc_newt() { for(int i = 1; i < max_n; ++i) { newt[i][0] = 1; newt[i][i] = 1; } for(int i = 2; i < max_n; ++i) { for(int j = 1; j < i; ++j) { newt[i][j] = (newt[i-1][j-1] + newt[i-1][j]) % p; } } } void print_s() { for(int i = 1; i <= lasts; ++i) { if (s[i] > 0) { printf(" (%d - %llu)", i, s[i]); } } printf("\n"); } void clean_s2(int a, int b) { for(int i = a; i <=b; ++i) { s2[i] = 0; } } unsigned long long calc_s() { unsigned long long result = 0; for(int x = 1; x <= b[0].num; ++x) { s[x] = newt[b[0].num][x]; } lasts = b[0].num; for(auto it = b.begin()+1; it != b.end(); ++it) { int val = it->val; int num = it->num; clean_s2(val+val-1, lasts); for(int x = 1; x <= num; ++x) { unsigned int count = newt[num][x]; unsigned int sum = val*x; for(int i = val-1; i <= lasts; ++i) { s2[sum+i] = (s2[sum+i] + (s[i]*count % p)) % p; } } for(int i = val+val-1; i <= val*num+lasts; ++i) { s[i] = (s[i] + s2[i]) % p; } lasts = val*num+lasts; // print_s(); } for(int i = 1; i <= lasts; ++i) { result = (result + s[i]) % p; } return result; } int main() { scanf("%d", &n); a.resize(max_val); for(int i = 0; i < n; ++i) { int x; scanf("%d", &x); a[x]++; } for(int i = 1; i < max_val; ++i) { node nd; if (a[i] > 0) { nd.val = i; nd.num = a[i]; b.push_back(nd); } } if (b[0].val != 1) { printf("0\n"); return 0; } calc_newt(); printf("%llu\n", calc_s()); //print_s(); return 0; } |