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;
}