矩阵乘法
/*
* 矩阵乘法 n*n矩阵乘法
*/
#define MAXN 111
#define mod(x) ((x) % MOD)
#define MOD 1000000007
#define LL long long
int n;
struct mat
{
int m[MAXN][MAXN];
};
// 矩阵乘法
mat operator * (mat a, mat &b)
{
mat ret;
memset(ret.m, 0, sizeof(ret.m));
for (int k = 0; k < n; k++)
{
for (int i = 0; i < n; i++)
{
if (a.m[i][k])
{
for (int j = 0; j < n; j++)
{
ret.m[i][j] = mod(ret.m[i][j] + (LL)a.m[i][k] * b.m[k][j]);
}
}
}
}
return ret;
}
矩阵乘法 + 判等
/*
* AB == C ???
*/
struct Matrix
{
Type mat[MAXN][MAXN];
int n, m;
Matrix()
{
n = m = MAXN;
memset(mat, 0, sizeof(mat));
}
Matrix(const Matrix &a)
{
set_size(a.n, a.m);
memcpy(mat, a.mat, sizeof(a.mat));
}
Matrix & operator = (const Matrix &a)
{
set_size(a.n, a.m);
memcpy(mat, a.mat, sizeof(a.mat));
return *this;
}
void set_size(int row, int column)
{
n = row;
m = column;
}
friend Matrix operator * (const Matrix &a, const Matrix &b)
{
Matrix ret;
ret.set_size(a.n, b.m);
for (int i = 0; i < a.n; ++i)
{
for (int k = 0; k < a.m; ++k)
{
if (a.mat[i][k])
{
for (int j = 0; j < b.m; ++j)
{
if (b.mat[k][j])
{
ret.mat[i][j] = ret.mat[i][j] + a.mat[i][k] * b.mat[k][j];
}
}
}
}
}
return ret;
}
friend bool operator == (const Matrix &a, const Matrix &b)
{
if (a.n != b.n || a.m != b.m)
{
return false;
}
for (int i = 0; i < a.n; ++i)
{
for (int j = 0; j < a.m; ++j)
{
if (a.mat[i][j] != b.mat[i][j])
{
return false;
}
}
}
return true;
}
};
矩阵快速幂
/*
* 矩阵快速幂 n*n矩阵的x次幂
*/
#define MAXN 111
#define mod(x) ((x) % MOD)
#define MOD 1000000007
#define LL long long
int n;
struct mat
{
int m[MAXN][MAXN];
} unit; // 单元矩阵
// 矩阵乘法
mat operator * (mat a, mat &b)
{
mat ret;
memset(ret.m, 0, sizeof(ret.m));
for (int k = 0; k < n; k++)
{
for (int i = 0; i < n; i++)
{
if (a.m[i][k])
{
for (int j = 0; j < n; j++)
{
ret.m[i][j] = mod(ret.m[i][j] + (LL)a.m[i][k] * b.m[k][j]);
}
}
}
}
return ret;
}
void init_unit()
{
for (int i = 0; i < MAXN; i++)
{
unit.m[i][i] = 1;
}
return ;
}
mat pow_mat(mat a, LL n)
{
mat ret = unit;
while (n)
{
if (n & 1)
{
// n--;
ret = ret * a;
}
n >>= 1;
a = a * a;
}
return ret;
}
int main()
{
LL x;
init_unit();
while (cin >> n >> x)
{
mat a;
for (int i = 0; i < n; i++)
{
for (int j = 0; j < n; j++)
{
cin >> a.m[i][j];
}
}
a = pow_mat(a, x); // a矩阵的x次幂
// 输出矩阵
for (int i = 0; i < n; i++)
{
for (int j = 0; j < n; j++)
{
if (j + 1 == n)
{
cout << a.m[i][j] << endl;
}
else
{
cout << a.m[i][j] << " ";
}
}
}
}
return 0;
}
2017.6.13 修改矩阵乘法部分,优化,引用、判0