数独解法C++実装

 
  
#include 
 
using namespace std;
 
/*        */
bool sign = false;
 
/*        */
int num[9][9];
 
/*      */
void Input();
void Output();
bool Check(int n, int key);
int DFS(int n);
 
/*     */
int main()
{
    cout << "     9*9     ，   0  :" << endl;
    Input();
    DFS(0);
    Output();
    system("pause");
}
 
/*        */
void Input()
{
    char temp[9][9];
    for (int i = 0; i < 9; i++)
    {
        for (int j = 0; j < 9; j++)
        {
            cin >> temp[i][j];
            num[i][j] = temp[i][j] - '0';
        }
    }
}
 
/*        */
void Output()
{
    cout << endl;
    for (int i = 0; i < 9; i++)
    {
        for (int j = 0; j < 9; j++)
        {
            cout << num[i][j] << " ";
            if (j % 3 == 2)
            {
                cout << "   ";
            }
        }
        cout << endl;
        if (i % 3 == 2)
        {
            cout << endl;
        }
    }
}
 
/*   key  n        */
bool Check(int n, int key)
{
    /*   n         */
    for (int i = 0; i < 9; i++)
    {
        /* j n    */
        int j = n / 9;
        if (num[j][i] == key) return false;
    }
 
    /*   n         */
    for (int i = 0; i < 9; i++)
    {
        /* j n    */
        int j = n % 9;
        if (num[i][j] == key) return false;
    }
 
    /* x n              */
    int x = n / 9 / 3 * 3;
 
    /* y n              */
    int y = n % 9 / 3 * 3;
 
    /*   n            */
    for (int i = x; i < x + 3; i++)
    {
        for (int j = y; j < y + 3; j++)
        {
            if (num[i][j] == key) return false;
        }
    }
 
    /*     ，     */
    return true;
}
 
/*        */
int DFS(int n)
{
    /*       ，     */
    if (n > 80)
    {
        sign = true;
        return 0;
    }
    /*           */
    if (num[n/9][n%9] != 0)
    {
        DFS(n+1);
    }
    else
    {
        /*              */
        for (int i = 1; i <= 9; i++)
        {
            /*           */
            if (Check(n, i) == true)
            {
                num[n/9][n%9] = i;
                /*      */
                DFS(n+1);
                /*          ，      */
                if (sign == true) return 0;
                /*        ，      */
                num[n/9][n%9] = 0;
            }
        }
    }
}