Submission #1001144

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Source Code Expand

// {{{ by shik
#include <bits/stdc++.h>
#include <unistd.h>
#define SZ(x) ((int)(x).size())
#define ALL(x) begin(x),end(x)
#define REP(i,n) for ( int i=0; i<int(n); i++ )
#define REP1(i,a,b) for ( int i=(a); i<=int(b); i++ )
#define FOR(it,c) for ( auto it=(c).begin(); it!=(c).end(); it++ )
#define MP make_pair
#define PB push_back
using namespace std;
typedef long long LL;
typedef pair<int,int> PII;
typedef vector<int> VI;

#ifdef SHIK
template<typename T>
void _dump( const char* s, T&& head ) { cerr<<s<<"="<<head<<endl; }

template<typename T, typename... Args>
void _dump( const char* s, T&& head, Args&&... tail ) {
    int c=0;
    while ( *s!=',' || c!=0 ) {
        if ( *s=='(' || *s=='[' || *s=='{' ) c++;
        if ( *s==')' || *s==']' || *s=='}' ) c--;
        cerr<<*s++;
    }
    cerr<<"="<<head<<", ";
    _dump(s+1,tail...);
}

#define dump(...) do { \
    fprintf(stderr, "%s:%d - ", __PRETTY_FUNCTION__, __LINE__); \
    _dump(#__VA_ARGS__, __VA_ARGS__); \
} while (0)

template<typename Iter>
ostream& _out( ostream &s, Iter b, Iter e ) {
    s<<"[";
    for ( auto it=b; it!=e; it++ ) s<<(it==b?"":" ")<<*it;
    s<<"]";
    return s;
}

template<typename A, typename B>
ostream& operator <<( ostream &s, const pair<A,B> &p ) { return s<<"("<<p.first<<","<<p.second<<")"; }
template<typename T>
ostream& operator <<( ostream &s, const vector<T> &c ) { return _out(s,ALL(c)); }
template<typename T, size_t N>
ostream& operator <<( ostream &s, const array<T,N> &c ) { return _out(s,ALL(c)); }
template<typename T>
ostream& operator <<( ostream &s, const set<T> &c ) { return _out(s,ALL(c)); }
template<typename A, typename B>
ostream& operator <<( ostream &s, const map<A,B> &c ) { return _out(s,ALL(c)); }
#else
#define dump(...)
#endif

template<typename T>
void _R( T &x ) { cin>>x; }
void _R( int &x ) { scanf("%d",&x); }
void _R( long long &x ) { scanf("%" PRId64,&x); }
void _R( double &x ) { scanf("%lf",&x); }
void _R( char &x ) { scanf(" %c",&x); }
void _R( char *x ) { scanf("%s",x); }

void R() {}
template<typename T, typename... U>
void R( T& head, U&... tail ) {
    _R(head);
    R(tail...);
}

template<typename T>
void _W( const T &x ) { cout<<x; }
void _W( const int &x ) { printf("%d",x); }
template<typename T>
void _W( const vector<T> &x ) {
    for ( auto i=x.cbegin(); i!=x.cend(); i++ ) {
        if ( i!=x.cbegin() ) putchar(' ');
        _W(*i);
    }
}

void W() {}
template<typename T, typename... U>
void W( const T& head, const U&... tail ) {
    _W(head);
    putchar(sizeof...(tail)?' ':'\n');
    W(tail...);
}

#ifdef SHIK
#define FILEIO(...)
#else
#define FILEIO(name) do {\
    freopen(name ".in","r",stdin); \
    freopen(name ".out","w",stdout); \
} while (0)
#endif

// }}}

const int N=10010;
const LL MOD=1e9+7;

LL inv[N],fac[N],ifac[N];
void predo() {
    inv[1]=1;
    REP1(i,2,N-1) inv[i]=inv[MOD%i]*(MOD-MOD/i)%MOD;
    fac[0]=1;
    REP1(i,1,N-1) fac[i]=fac[i-1]*i%MOD;
    ifac[0]=1;
    REP1(i,1,N-1) ifac[i]=ifac[i-1]*inv[i]%MOD;
}

LL C( int n, int m ) {
    return fac[n]*ifac[m]%MOD*ifac[n-m]%MOD;
}

LL H( int n, int m ) {
    if ( n==0 && m==0 ) return 1;
    return C(n-1+m,m);
}

int n,a,b,c;

int solve() {
    if ( b%2!=0 ) return 0;
    b/=2;
    LL ans=0;
    REP1(i,0,c) {
        REP1(j,0,min(a,c-i)) {
            int k=c-i-j;
            if ( k%3!=0 ) continue;
            k/=3;
            LL now=H(b,i);
            now=now*H(b+1,k)%MOD;
            now=now*H(b+1+k,j)%MOD;
            now=now*H(b+1+k+j,a-j)%MOD;
            dump(i,j,k,now);
            ans+=now;
        }
    }
    ans%=MOD;
    return ans;
}

bool vis[N];
int slow_ans;
void dfs( int x, int t[3] ) {
    if ( t[0]>a || t[1]>b || t[2]>c ) return;
    // dump(x,t[0],t[1],t[2],x+2,vis[3],n);
    if ( x==n ) {
        if ( t[0]==a && t[1]==b && t[2]==c ) slow_ans++;
        return;
    }
    if ( vis[x] ) {
        dfs(x+1,t);
        return;
    }
    REP1(i,1,3) if ( x+i<n && !vis[x+i] ) {
        vis[x+i]=1;
        t[i-1]++;
        dfs(x+1,t);
        t[i-1]--;
        vis[x+i]=0;
    }
}

int main() {
    predo();
    R(n,a,b,c);
    n=2*(a+b+c);
    // int t[3]={};
    // dfs(0,t);
    // dump(slow_ans);
    int ans=solve();
    W(ans);
    return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘void _R(long long int&)’:
./Main.cpp:62:46: warning: format ‘%ld’ expects argument of type ‘long int*’, but argument 2 has type ‘long long int*’ [-Wformat=]
 void _R( long long &x ) { scanf("%" PRId64,&x); }
                                              ^
./Main.cpp: In function ‘void _R(int&)’:
./Main.cpp:61:35: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
 void _R( int &x ) { scanf("%d",&x); }
                                   ^
./Main.cpp: In function ‘void _R(long long int&)’:
./Main.cpp:62:47: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
 void _R( long long &x ) { scanf("%" PRId64,&x); }
                                               ^
./Main.cpp: In function ‘void _R(double&)’:
./Main.cpp:63:39: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-resu...

Judge Result