Bzoj 3534 ([Sdoi2014] Reconstruction-Variable matrix-Tree theorem-Benquan product and all spanning trees)

The

variable-element matrix-Tree theorem, which is the Benquan of the product of all spanning trees. Change the degree to connect the Benquan and, a[i][j]=−a[i][j]=-edge right, a[i][i]= a[i][i]= to connect out of Benquan and.

#include <bits/stdc++.h> using namespace std; #define for (I,n) for (int. i=1;i<=n;i++) #define FORK (I,k,n) for (int. i=k;i<=n;i++) #define FORKD (i,k,n) for (int i=n;i >=k;i--) #define REP (I,n) for (int. i=0;i<n;i++) #define ForD (I,n) for (int. i=n;i;i--) #define REPD (i,n) for (int i=n;i& gt;=0;i--) #define FORP (x) for (int p=pre[x];p, p=next[p]) #define FORPITER (x) for (int &p=iter[x];p; p=next[p]) #defin
E Lson (o<<1) #define Rson ((o<<1) +1) #define MEM (a) memset (A,0,sizeof (a));
#define MEMI (a) memset (A,0x3f,sizeof (a));
#define MEMI (a) memset (A,128,sizeof (a));
#define MEMX (A, B) memset (A,b,sizeof (a)); #define INF (0x3f3f3f3f) #define F (1000000007) #define PB push_back #define MP Make_pair #define FI first #define SE seco nd #define VI vector<int> #define PI pair<int,int> #define SI (a) ((a). Size ()) #define PR (Kcase,ans) printf ("C
ASE #%d:%lld\n ", Kcase,ans); #define PRI (A,n) for (i,n-1) cout<<a[i]<< ";
cout<<a[n]<<endl; #define PRi2D (a,n,m) for (i,n) {\ for (j,m-1) cout<<a[i][j]<< '; \ cout< <a[i][m]<<endl; \} #pragma COMMENT (linker, "/stack:102400000,102400000") #define ALL (x) (x). Begin (), (x). End () Ty
Pedef Long Long ll;
typedef long double LD;
typedef unsigned long long ull;  LL Mul (ll A,ll b) {return (a*b)%F;} ll Add (ll A,ll b) {return (a+b)%F;} ll Sub (ll A,ll b) {return ((a)%f+f)%F; void Upd (LL
    &a,ll b) {a= (a%f+b%f)%F;} inline int read () {int x=0,f=1; char Ch=getchar ();
    while (!isdigit (CH)) {if (ch== '-') f=-1; Ch=getchar ();}
    while (IsDigit (ch)) {x=x*10+ch-' 0 '; Ch=getchar ();}
return x*f;
} #define EPS (1e-8) #define MAXN (305) int n;
Double A[MAXN][MAXN];
    Double det (int n) {bool f=0;
        for (i,n) {int k=0;
        Fork (J,i,n) if (Fabs (A[j][i]) >fabs (A[k][i])) {k=j;}
        for (j,n) swap (a[i][j],a[k][j]);
        if (i^k) f^=1;
        if (Fabs (A[i][i]) <eps) continue; ForK (j,i+1,n) {double t=a[j][i]/(a[i][i]);
            Fork (k,i,n) {a[j][k]-=t*a[i][k];
    }}} double r=1;
    for (I,n) r=r*a[i][i];
    if (f) r=-r;
return R;
    } int main () {///Freopen ("Bzoj3534.in", "R", stdin);//Freopen (". Out", "w", stdout);
    int N=read ();
    MEM (a) double p=1;
        for (I,n) for (j,n) {double pp=0;
        scanf ("%lf", &pp);
        if (i^j) a[i][j]=pp;
        if (i<j) p*=1-a[i][j];
        if (i^j) a[i][j]/=1-a[i][j];
            if (i^j) {a[i][i]+=a[i][j];//A[J][J]+=A[I][J];   
        A[I][J]=-A[I][J];


    }} printf ("%.10lf\n", Det (n-1) *p);
return 0;
 }