mirror of
https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
80 lines
1.9 KiB
C++
80 lines
1.9 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 <vector>
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#include <queue>
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#include <set>
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#include <map>
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#include <string>
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#include <math.h>
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#include <stdlib.h>
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#include <time.h>
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using namespace std;
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const double eps = 1e-9;
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const int MAXN = 100;
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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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{
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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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{
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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(int i = 0;i < equ;i++)
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if(i != k)
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{
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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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int main()
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{
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int n,m;
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int T;
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int iCase = 0;
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scanf("%d",&T);
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while(T--)
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{
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iCase++;
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scanf("%d%d",&n,&m);
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equ = var = n;
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memset(a,0,sizeof(a));
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int u,v,w;
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for(int i = 0;i < m;i++)
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{
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scanf("%d%d%d",&u,&v,&w);
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a[u-1][v-1] += 1.0/w;
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a[u-1][u-1] += -1.0/w;
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a[v-1][u-1] += 1.0/w;
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a[v-1][v-1] += -1.0/w;
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}
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for(int i = 0;i < n-1;i++)
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x[i] = 0;
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x[0] = 1;
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for(int i = 0;i < n;i++)
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a[n-1][i] = 0;
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x[n-1] = 0;
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a[n-1][0] = 1;
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Gauss();
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printf("Case #%d: %.2lf\n",iCase,x[n-1]);
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}
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return 0;
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}
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