高斯消元异或版模板

/**2016 - 09 - 08 晚上Author: ITAKMotto:今日的我要超越昨日的我，明日的我要胜过今日的我，以创作出更好的代码为目标，不断地超越自己。**/#include <iostream>#include <cstdio>#include <cstring>#include <cstdlib>#include <cmath>#include <vector>#include <queue>#include <algorithm>#include <set>using namespace std;typedef long long LL;typedef unsigned long long ULL;const int INF = 1e9+5;const int MAXN = 400;const int MOD = 1e9+7;const double eps = 1e-7;const double PI = acos(-1);using namespace std;LL Scan_LL()///输入外挂{    LL res=0,ch,flag=0;    if((ch=getchar())=='-')        flag=1;    else if(ch>='0'&&ch<='9')        res=ch-'0';    while((ch=getchar())>='0'&&ch<='9')        res=res*10+ch-'0';    return flag?-res:res;}int Scan_Int()///输入外挂{    int res=0,ch,flag=0;    if((ch=getchar())=='-')        flag=1;    else if(ch>='0'&&ch<='9')        res=ch-'0';    while((ch=getchar())>='0'&&ch<='9')        res=res*10+ch-'0';    return flag?-res:res;}void Out(LL a)///输出外挂{    if(a>9)        Out(a/10);    putchar(a%10+'0');}int equ, var;///equ个方程 var个变量int a[MAXN][MAXN];///增广矩阵int x[MAXN];///解集int x_i[MAXN];bool free_x[MAXN];///判断是不是自由变元int free_num;///自由变元的个数int Gauss(){    int Max_r;///当前列绝对值最大的存在的行    ///col：处理当前的列    int row,col = 0;    int free_x_num;    int free_index;    free_num = 0;    for(int i=0; i<=var; i++)    {        x[i] = 0;        free_x[i] = 1;    }    for(row=0; row<equ&&col<var; row++,col++)    {        Max_r = row;        for(int i=row+1; i<equ; i++)            if(abs(a[i][col]) > abs(a[Max_r][col]))                Max_r = i;        if(a[Max_r][col] == 0)        {            free_x[col] = 1;            x_i[free_num++] = col;            row--;            continue;        }        if(Max_r != row)            for(int i=col; i<var+1; i++)                swap(a[row][i], a[Max_r][i]);        ///消元        for(int i=row+1; i<equ; i++)            if(a[i][col])                for(int j=col; j<var+1; j++)                    a[i][j] ^= a[row][j];    }    for(int i=row; i<equ; i++)        if(a[i][col])            return -1;///无解    ///保证对角线主元非 0    for(int i=0;  i<equ; i++)    {        if(!a[i][i])        {            int j;            for(j=i+1; j<var; j++)                if(a[i][j])                    break;            if(j == var)                break;            for(int k=0; k<equ; k++)                swap(a[k][i], a[k][j]);        }    }    if(row < var)        return var - row;///自由变元的个数    ///回代，得到解集    for(int i=var-1; i>=0; i--)    {        x[i] = a[i][var];        for(int j=i+1; j<var; j++)            x[i] ^= (a[i][j] && x[j]);    }    return 0;///唯一解}void Debug(){    puts("");    cout<<"+++++++++++++++++++++++++++分界线++++++++++++++++++++++++++++++"<<endl;    for(int i=0; i<equ; i++)    {        for(int j=0; j<var+1; j++)        {            cout<<a[i][j]<<" ";        }        cout<<endl;    }    cout<<"+++++++++++++++++++++++++++分界线++++++++++++++++++++++++++++++"<<endl;    puts("");}int main(){    while(cin>>equ>>var)    {        for(int i=0; i<equ; i++)        {            for(int j=0; j<var+1; j++)                cin>>a[i][j];        }        ///Debug();        cout<<Gauss()<<endl;    }    return 0;}