125 lines
3.0 KiB
C++
125 lines
3.0 KiB
C++
#include <stdio.h>
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#include <string.h>
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#include <iostream>
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#include <algorithm>
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#include <queue>
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#include <map>
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#include <set>
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#include <vector>
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#include <string>
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#include <math.h>
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using namespace std;
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#define eps 1e-6
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const int MAXN=220;
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double a[MAXN][MAXN],x[MAXN];
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int equ,var;
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int Gauss()
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{
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int i,j,k,col,max_r;
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for(k=0,col=0;k<equ&&col<var;k++,col++){
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max_r = k;
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for(i=k+1;i<equ;i++)
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if(fabs(a[i][col])>fabs(a[max_r][col]))
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max_r = i;
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if(fabs(a[max_r][col])<eps)return 0;
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if(k != max_r){
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for(j=col;j<var;j++)
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swap(a[k][j],a[max_r][j]);
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swap(x[k],x[max_r]);
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}
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x[k]/=a[k][col];
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for(j=col+1;j<var;j++)a[k][j]/=a[k][col];
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a[k][col] = 1;
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for(i=0;i<equ;i++)
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if(i!=k){
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x[i] -= x[k]*a[i][k];
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for(j=col+1;j<var;j++)a[i][j]-=a[k][j]*a[i][col];
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a[i][col]=0;
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}
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}
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return 1;
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}
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vector<int>vec[MAXN];
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int g[MAXN][MAXN];
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int du[MAXN];
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int add[MAXN];
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int main()
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{
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int T;
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int n,m;
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scanf("%d",&T);
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while(T--)
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{
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scanf("%d%d",&n,&m);
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for(int i = 0;i < n;i++)
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vec[i].clear();
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memset(g,0,sizeof(g));
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memset(du,0,sizeof(du));
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int u,v;
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while(m--)
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{
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scanf("%d%d",&u,&v);
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if(u == v)continue;
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g[u][v] = 1;
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}
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for(int i = 0;i < n;i++)
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{
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for(int j = 0;j < n;j++)
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if(j != i && g[i][j])
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{
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du[i]++;
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vec[j].push_back(i);
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}
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}
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equ = var = n;
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for(int i = 0;i < n;i++)
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x[i] = 0;
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memset(a,0,sizeof(a));
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for(int i = 0;i < n;i++)
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{
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a[i][i] = -1;
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int sz = vec[i].size();
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for(int j = 0;j < sz;j++)
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{
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int v = vec[i][j];
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if(i == v)continue;
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a[i][v] = 1.0 / du[v];
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}
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}
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for(int i = 0;i < n;i++)
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a[n-1][i] = 1;
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x[n-1] = 1;
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for(int k = 0;k < n-1;k++)
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if(g[n-1][k] == 0)
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{
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for(int i = 0;i < n-1;i++)
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{
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if(g[n-1][i])a[i][var] = 1.0/(du[n-1]+1);
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else a[i][var] = 0;
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}
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a[k][var] = 1.0/(du[n-1]+1);
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a[n-1][var] = 1;
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add[var] = k;
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var++;
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}
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if(!Gauss())
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{
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printf("INF\n");
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continue;
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}
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double tt = x[n-1];
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double now = x[n-1];
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int ans = -1;
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for(int i = n;i < var;i++)
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{
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if(x[n-1]/a[n-1][i] > now)
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{
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ans = add[i];
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now = x[n-1]/a[n-1][i];
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}
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}
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printf("%d %d\n",1,ans);
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}
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return 0;
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}
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