OJ-Problems-Source/HDOJ/3976_autoAC.cpp
2016-09-04 14:19:03 +08:00

80 lines
1.9 KiB
C++

#include <stdio.h>
#include <string.h>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <math.h>
#include <stdlib.h>
#include <time.h>
using namespace std;
const double eps = 1e-9;
const int MAXN = 100;
double a[MAXN][MAXN],x[MAXN];
int equ,var;
int Gauss()
{
int i,j,k,col,max_r;
for(k = 0,col = 0;k < equ && col < var;k++,col++)
{
max_r = k;
for(i = k+1;i < equ;i++)
if(fabs(a[i][col]) > fabs(a[max_r][col]))
max_r = i;
if(fabs(a[max_r][col]) < eps)return 0;
if(k != max_r)
{
for(j = col;j < var;j++)
swap(a[k][j],a[max_r][j]);
swap(x[k],x[max_r]);
}
x[k]/=a[k][col];
for(j = col+1;j < var;j++)a[k][j]/=a[k][col];
a[k][col] = 1;
for(int i = 0;i < equ;i++)
if(i != k)
{
x[i] -= x[k]*a[i][k];
for(j = col+1;j < var;j++)a[i][j] -= a[k][j]*a[i][col];
a[i][col] = 0;
}
}
return 1;
}
int main()
{
int n,m;
int T;
int iCase = 0;
scanf("%d",&T);
while(T--)
{
iCase++;
scanf("%d%d",&n,&m);
equ = var = n;
memset(a,0,sizeof(a));
int u,v,w;
for(int i = 0;i < m;i++)
{
scanf("%d%d%d",&u,&v,&w);
a[u-1][v-1] += 1.0/w;
a[u-1][u-1] += -1.0/w;
a[v-1][u-1] += 1.0/w;
a[v-1][v-1] += -1.0/w;
}
for(int i = 0;i < n-1;i++)
x[i] = 0;
x[0] = 1;
for(int i = 0;i < n;i++)
a[n-1][i] = 0;
x[n-1] = 0;
a[n-1][0] = 1;
Gauss();
printf("Case #%d: %.2lf\n",iCase,x[n-1]);
}
return 0;
}