Poj1830开关问题，高斯消元

高斯消元的入门题。

#include<iostream>

#include<cstdio>

#include<cstring>

#include<map>

#include<vector>

#include<stdlib.h>

using namespace std;



int Map[100][100];



int gauss(int equ, int var)

{

    int k; int col;

    for (k = 0, col = 0; k < equ&&col < var; k++, col++){

        int kk = k;

        for (int i = k + 1; i < equ; i++){

            if (Map[i][col]>Map[kk][col])kk = i;

        }

        if (kk != k){

            for (int j = k; j <= var; j++)

                swap(Map[k][j], Map[kk][j]);

        }

        if (Map[k][col] == 0){

            k--; continue;

        }

        for (int i = k + 1; i < equ; i++){

            if (Map[i][col]){

                for (int j = col; j <= var; j++){

                    Map[i][j] ^= Map[k][j];

                }

            }

        }

    }

    for (int i = k; i < equ; i++){

        if (Map[i][col]) return -1;

    }

    return col - k;

}

int main()

{

    int k; int n;

    int a[100], b[100];

    int c; int d;

    cin >> k;

    while (k--){

        cin >> n;

        memset(Map, 0, sizeof(Map));

        for (int i = 0; i < n; i++)

            scanf("%d", &a[i]);

        for (int i = 0; i < n; i++)

            scanf("%d", &b[i]);

        for (int i = 0; i < n; i++)

            a[i] = (a[i] ^ b[i]);

        for (int i = 0; i < n; i++)

            Map[i][n] = a[i];

        for(int i =0;i<n;i++)

            Map[i][i] = 1;

        while (cin >> c >> d, c || d){

            c--;d--;

            Map[d][c] = 1;

        }

        int ans = 1;

        int t = gauss(n, n);

        if(t==-1){

            cout<<"Oh,it's impossible~!!"<<endl;

            continue;

        }

        for (int i = 0; i < t; i++)

            ans *= 2;

        cout << ans << endl;

    }

    return 0;

}