Summer Practice Diary (iii)

Switching problems

Time Limit: 1000MS		Memory Limit: 30000K
Total Submissions: 6455		Accepted: 2463

Description

There are n the same switch, each switch is associated with some switches, each time you open or close a switch, the other switches associated with this switch will also change accordingly, that is, the status of the connected switch if the original is turned off, if it is turned on. Your goal is to make the last n switches reach a specific state after several switching operations. For any switch, a maximum of one switch operation can be performed. Your task is to calculate how many methods are available to reach the specified state. (regardless of the order of the switching operation)

Input

Enter the first line with a number k, indicating that the following k sets of test data are available.
The format of each set of test data is as follows:
First row one number N (0 < N < 29)
The second row n 0 or 1 of the number, indicating the start of N switch state.
The third row n 0 or 1, indicating the state of n switches after the end of the operation.
The next two number I J for each line indicates that the status of the J switch will change if the I switch is operated. Each set of data ends with 0 0.

Output

If there is a viable method, the total output, otherwise the output "Oh,it ' s impossible~!!" does not include quotation marks

Sample Input

230 0 01 1 11 21 32 12 33 13 20 030 0 01 0 11 22 10 0

Sample Output

4oh,it ' s impossible~!!

Hint

Description of the first set of data:
Altogether the following four methods:
Operation Switch 1
Operation Switch 2
Operation Switch 3
Operating switches 1, 2, 3 (no order)

Source

[email protected]This to the topic is the typical application of the Gaussian elimination method. The relationship between all switches is treated as a factor, while the operation on the switch acts as a variable. In this way, the coefficient matrix and the variable matrix are formed. It is important to note that the values in each row of the coefficient matrix A[i][j] Indicate whether J has an effect on I. Code:

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Zfy11 ' s source code for B

Memory: 148 KB		Time : 0 MS
Language: C++		Result: Accepted
Public:		NoYes

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#include<cstdio>#include<cstring>#include<cmath>#include<cstdlib>#include<algorithm>#include<vector>#include<map>#include<iostream>UsingNamespace Std;Constint MAXN=60;int a[MAXN][maxn];int x[MAXN];int free_x[MAXN];IntGauss(int equ,int var){int IJK, Max_r, col;For(int I=0; I<=var; I++){x[I]=0; Free_x[I]=1;} col=0;For(k=0; k<equ&&col<var; k++,col++){Max_r=k;For(I=k+1; I<equ; I++){If(Abs(A[I][col]) >Abs(A[Max_r][col])) Max_r=i;}If(Max_r!=k){For(j=k; j<var+1; j++)Swap(A[k][j],a[Max_r][j]);}If(A[k][col]==0){k--;Continue;}For(I=k+1; I<equ; I++){If(A[I][col]!=0){For(j=col; j<var+1; j+ +) A[I][j]^=a[k][j];}}}For(I=k; I<equ; I++){If(A[I][col]!=0)Return-1;}return var-K;}int start[MAXN];int end[MAXN];IntMain(){int n;int sE;int T;scanf("%d", &t);While(T--){scanf("%d", &n);For(int I=0; I<n; I++){scanf("%d", &start[I]);}For(int I=0; I<n; I++){scanf("%d", &end[I]);}Memset(A,0,sizeof(A));While(scanf("%d%d", &s, &e)){If(s==0&&e==0)Break; A[E-1][s-1]=1;}For(int I=0; I<n; I+ +) A[I][i]=1;For(int I=0; I<n; I+ +) A[I][n]=start[I]^end[I];int ans=Gauss(n,n); if (Ans==-1< Span class= "Sh-symbol" >) printf (\n "); else printf ( "%d\n" ,1< Span class= "Sh-symbol" ><<ans);  return 0;< Span class= "Sh-cbracket" >             

Summer Practice Diary (iii)