Submission #3888920
Source Code Expand
#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/rope>
using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;
typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;
typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define F0R(i, a) for (int i = 0; i < (a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= (a); i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)
#define trav(a, x) for (auto& a : x)
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define sz(x) (int)x.size()
#define beg(x) x.begin()
#define en(x) x.end()
#define all(x) beg(x), en(x)
#define resz resize
const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 2001;
const ld PI = 4*atan((ld)1);
template<class T> void ckmin(T &a, T b) { a = min(a, b); }
template<class T> void ckmax(T &a, T b) { a = max(a, b); }
namespace io {
// TYPE ID (StackOverflow)
template<class T> struct like_array : is_array<T>{};
template<class T, size_t N> struct like_array<array<T,N>> : true_type{};
template<class T> struct like_array<vector<T>> : true_type{};
template<class T> bool is_like_array(const T& a) { return like_array<T>::value; }
// I/O
void setIn(string s) { freopen(s.c_str(),"r",stdin); }
void setOut(string s) { freopen(s.c_str(),"w",stdout); }
void setIO(string s = "") {
ios_base::sync_with_stdio(0); cin.tie(0);
if (sz(s)) { setIn(s+".in"), setOut(s+".out"); }
}
// INPUT
template<class T> void re(T& x) { cin >> x; }
template<class Arg, class... Args> void re(Arg& first, Args&... rest);
void re(double& x) { string t; re(t); x = stod(t); }
void re(ld& x) { string t; re(t); x = stold(t); }
template<class T> void re(complex<T>& x);
template<class T1, class T2> void re(pair<T1,T2>& p);
template<class T> void re(vector<T>& a);
template<class T, size_t SZ> void re(array<T,SZ>& a);
template<class Arg, class... Args> void re(Arg& first, Args&... rest) { re(first); re(rest...); }
template<class T> void re(complex<T>& x) { T a,b; re(a,b); x = cd(a,b); }
template<class T1, class T2> void re(pair<T1,T2>& p) { re(p.f,p.s); }
template<class T> void re(vector<T>& a) { F0R(i,sz(a)) re(a[i]); }
template<class T, size_t SZ> void re(array<T,SZ>& a) { F0R(i,SZ) re(a[i]); }
// OUTPUT
template<class T1, class T2> ostream& operator<<(ostream& os, const pair<T1,T2>& a) {
os << '{' << a.f << ", " << a.s << '}'; return os;
}
template<class T> ostream& printArray(ostream& os, const T& a, int SZ) {
os << '{';
F0R(i,SZ) {
if (i) {
os << ", ";
if (is_like_array(a[i])) cout << "\n";
}
os << a[i];
}
os << '}';
return os;
}
template<class T, size_t SZ> ostream& operator<<(ostream& os, const array<T,SZ>& a) {
return printArray(os,a,SZ);
}
template<class T> ostream& operator<<(ostream& os, const vector<T>& a) {
return printArray(os,a,sz(a));
}
template<class T> ostream& operator<<(ostream& os, const set<T>& a) {
os << vector<T>(all(a)); return os;
}
template<class T1, class T2> ostream& operator<<(ostream& os, const map<T1,T2>& a) {
os << vector<pair<T1,T2>>(all(a)); return os;
}
template<class T> void pr(const T& x) { cout << x << '\n'; }
template<class Arg, class... Args> void pr(const Arg& first, const Args&... rest) {
cout << first << ' '; pr(rest...);
}
}
using namespace io;
namespace modOp {
int ad(int a, int b, int mod = MOD) { return (a+b)%mod; }
int sub(int a, int b, int mod = MOD) { return (a-b+mod)%mod; }
int mul(int a, int b, int mod = MOD) { return (ll)a*b%mod; }
int AD(int& a, int b, int mod = MOD) { return a = ad(a,b,mod); }
int SUB(int& a, int b, int mod = MOD) { return a = sub(a,b,mod); }
int MUL(int& a, int b, int mod = MOD) { return a = mul(a,b,mod); }
int po (int b, int p, int mod = MOD) { return !p?1:mul(po(mul(b,b,mod),p/2,mod),p&1?b:1,mod); }
int inv (int b, int mod = MOD) { return po(b,mod-2,mod); }
int invGeneral(int a, int b) { // 0 < a < b, gcd(a,b) = 1
if (a == 0) return b == 1 ? 0 : -1;
int x = invGeneral(b%a,a);
return x == -1 ? -1 : ((1-(ll)b*x)/a+b)%b;
}
}
using namespace modOp;
void AD(array<int,4>& a, array<int,4> b) {
F0R(i,4) AD(a[i],b[i]);
}
int N, p[MX], fac[MX], ans;
vector<array<int,4>> dp[MX];
void comb(vector<array<int,4>>& a, vector<array<int,4>> b) {
vector<array<int,4>> c(sz(a)+sz(b));
F0R(i,sz(a)) F0R(j,sz(b)) {
F0R(I,4) F0R(J,4) AD(c[i+j][I],mul(a[i][I],b[j][J]));
AD(c[i+j+1][1],mul(a[i][0],b[j][0])); AD(c[i+j+1][2],mul(a[i][0],b[j][0]));
AD(c[i+j+1][1],mul(a[i][0],b[j][1]));
AD(c[i+j+1][2],mul(a[i][0],b[j][2]));
AD(c[i+j+1][3],mul(a[i][1],b[j][0])); AD(c[i+j+1][3],mul(a[i][1],b[j][2]));
AD(c[i+j+1][3],mul(a[i][2],b[j][0])); AD(c[i+j+1][3],mul(a[i][2],b[j][1]));
}
swap(a,c);
}
int main() {
// you should actually read the stuff at the bottom
setIO(); re(N);
FOR(i,2,N+1) re(p[i]);
FOR(i,1,N+1) dp[i].pb({1,0,0,0});
FORd(i,2,N+1) comb(dp[p[i]],dp[i]);
fac[0] = 1;
FOR(i,1,N+1) fac[i] = mul(i,fac[i-1]);
// pr(dp[1]);
F0R(i,N) {
int prod = 0; F0R(j,4) AD(prod,dp[1][i][j]);
MUL(prod,fac[N-i]);
if (i&1) SUB(ans,prod);
else AD(ans,prod);
}
pr(ans);
// you should actually read the stuff at the bottom
}
/* stuff you should look for
* int overflow, array bounds
* special cases (n=1?), set tle
* do smth instead of nothing and stay organized
*/
Submission Info
Submission Time |
|
Task |
A - Awkward |
User |
Benq |
Language |
C++14 (GCC 5.4.1) |
Score |
1000 |
Code Size |
6510 Byte |
Status |
AC |
Exec Time |
210 ms |
Memory |
48896 KB |
Compile Error
./Main.cpp: In function ‘void io::setIn(std::string)’:
./Main.cpp:67:56: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result]
void setIn(string s) { freopen(s.c_str(),"r",stdin); }
^
./Main.cpp: In function ‘void io::setOut(std::string)’:
./Main.cpp:68:58: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result]
void setOut(string s) { freopen(s.c_str(),"w",stdout); }
^
Judge Result
Set Name |
Sample |
All |
Score / Max Score |
0 / 0 |
1000 / 1000 |
Status |
|
|
Set Name |
Test Cases |
Sample |
a01, a02, a03, a04 |
All |
a01, a02, a03, a04, b05, b06, b07, b08, b09, b10, b11, b12, b13, b14, b15, b16, b17, b18, b19, b20, b21, b22, b23, b24, b25, b26, b27, b28, b29, b30, b31, b32, b33, b34, b35, b36, b37, b38, b39, b40, b41, b42, b43, b44, b45, b46, b47, b48, b49, b50, b51, b52, b53, b54, b55 |
Case Name |
Status |
Exec Time |
Memory |
a01 |
AC |
1 ms |
256 KB |
a02 |
AC |
1 ms |
256 KB |
a03 |
AC |
1 ms |
256 KB |
a04 |
AC |
1 ms |
256 KB |
b05 |
AC |
1 ms |
256 KB |
b06 |
AC |
178 ms |
512 KB |
b07 |
AC |
198 ms |
31744 KB |
b08 |
AC |
167 ms |
768 KB |
b09 |
AC |
167 ms |
640 KB |
b10 |
AC |
167 ms |
640 KB |
b11 |
AC |
167 ms |
512 KB |
b12 |
AC |
168 ms |
512 KB |
b13 |
AC |
168 ms |
512 KB |
b14 |
AC |
172 ms |
512 KB |
b15 |
AC |
167 ms |
768 KB |
b16 |
AC |
43 ms |
512 KB |
b17 |
AC |
2 ms |
384 KB |
b18 |
AC |
1 ms |
256 KB |
b19 |
AC |
167 ms |
768 KB |
b20 |
AC |
167 ms |
640 KB |
b21 |
AC |
167 ms |
640 KB |
b22 |
AC |
167 ms |
768 KB |
b23 |
AC |
167 ms |
516 KB |
b24 |
AC |
167 ms |
640 KB |
b25 |
AC |
169 ms |
3328 KB |
b26 |
AC |
178 ms |
512 KB |
b27 |
AC |
182 ms |
20352 KB |
b28 |
AC |
177 ms |
512 KB |
b29 |
AC |
199 ms |
36096 KB |
b30 |
AC |
195 ms |
32000 KB |
b31 |
AC |
194 ms |
33280 KB |
b32 |
AC |
198 ms |
30976 KB |
b33 |
AC |
167 ms |
896 KB |
b34 |
AC |
168 ms |
1920 KB |
b35 |
AC |
168 ms |
1792 KB |
b36 |
AC |
167 ms |
768 KB |
b37 |
AC |
167 ms |
768 KB |
b38 |
AC |
167 ms |
768 KB |
b39 |
AC |
167 ms |
896 KB |
b40 |
AC |
167 ms |
768 KB |
b41 |
AC |
167 ms |
768 KB |
b42 |
AC |
167 ms |
640 KB |
b43 |
AC |
167 ms |
768 KB |
b44 |
AC |
168 ms |
896 KB |
b45 |
AC |
205 ms |
41856 KB |
b46 |
AC |
209 ms |
48896 KB |
b47 |
AC |
206 ms |
42752 KB |
b48 |
AC |
210 ms |
48256 KB |
b49 |
AC |
204 ms |
38656 KB |
b50 |
AC |
177 ms |
512 KB |
b51 |
AC |
178 ms |
512 KB |
b52 |
AC |
178 ms |
512 KB |
b53 |
AC |
178 ms |
512 KB |
b54 |
AC |
178 ms |
512 KB |
b55 |
AC |
194 ms |
23808 KB |