[英]C programming - Sodoku solution (backtracking)
the Question is: to get from the user sodoku board and if there is a solution to print it, if not to print no solution: the solution of the soduko;问题是:从用户sodoku board获得,如果有解决方案打印它,如果没有打印没有解决方案:soduko的解决方案; two identical numbers mmust not appear on the same line.
两个相同的数字不得出现在同一行。 two identical numbers must not appear in the same colum.
两个相同的数字不能出现在同一列中。 I worte a program that works perfectly when I put the soduko board and the size (global parametes-as shown un my code) but when I tried to receive from the user it took so much time to run the solution and sometimes it didn't retun anything?
我编写了一个程序,当我放置 soduko 板和尺寸(全局参数 - 如我的代码所示)时,我编写了一个运行良好的程序,但是当我尝试从用户那里接收时,运行解决方案花费了很多时间,有时它没有退还什么? I would like to understand why?!
我想知道为什么?!
#include <stdio.h>
#include <stdlib.h>
#define SIZE 5
int matrix[5][5] = {
{4,2,0,0,5},
{2,0,0,1,3},
{5,0,1,2,0},
{0,0,3,0,2},
{0,0,0,0,0},
};
void print_sudoku()
{
int i,j;
for(i=0;i<SIZE;i++)
{
for(j=0;j<SIZE;j++)
{
printf("%d ",matrix[i][j]);
}
printf("\n");
}
}
int number_unassigned(int *row, int *col)
{
int num_unassign = 0;
int i,j;
for(i=0;i<SIZE;i++)
{
for(j=0;j<SIZE;j++)
{
if(matrix[i][j] == 0)
{
*row = i;
*col = j;
num_unassign = 1;
return num_unassign;
}
}
}
return num_unassign;
}
int is_safe(int n, int r, int c)
{
int i;
for(i=0;i<SIZE;i++)
{
if(matrix[r][i] == n)
return 0;
}
for(i=0;i<SIZE;i++)
{
if(matrix[i][c] == n)
return 0;
}
return 1;
}
int solve_sudoku()
{
int row;
int col;
if(number_unassigned(&row, &col) == 0)
return 1;
int i;
for(i=1;i<=SIZE;i++)
{
if(is_safe(i, row, col))
{
matrix[row][col] = i;
if(solve_sudoku())
return 1;
matrix[row][col]=0;
}
}
return 0;
}
int main()
{
if (solve_sudoku())
print_sudoku();
else
printf("No solution!\n");
return 0;
}
and this is whe code that I used to ask the user to enter a sodoku board:这就是我用来要求用户输入数独板的代码:
int** ReadSoduko(int n) {
int** matrix = (int**) malloc((sizeof(int*)) * n);
for(int i = 0; i < n; ++i) {
matrix[i] = malloc(sizeof(int) * n);
}
printf("\nEnter your soduko board:\n");
for(int i = 0; i < n; ++i) {
printf("Enter row [%d]: ", i);
for(int j = 0; j < n; ++j) {
scanf("%d", &matrix[i][j]);
}
}
return matrix;
}
I suspect your problem is related to one thing: #define SIZE
that you are probably forgetting to update when reading dynamically.我怀疑您的问题与一件事有关:
#define SIZE
您可能在动态阅读时忘记更新。 Since you use SIZE
in your loops, if that is not the real size of your matrix, then it probably won't work.由于您在循环中使用了
SIZE
,如果这不是矩阵的实际大小,那么它可能不起作用。 I've changed 2 lines and added 3 other (the lines with comments at the end).我更改了 2 行并添加了其他 3 行(末尾带有注释的行)。 Try it now.
现在就试试。
#include <stdio.h>
#include <stdlib.h>
int SIZE; //changed here
int** matrix; //changed here
void print_sudoku()
{
int i, j;
for (i = 0; i < SIZE; i++)
{
for (j = 0; j < SIZE; j++)
{
printf("%d ", matrix[i][j]);
}
printf("\n");
}
}
int number_unassigned(int* row, int* col)
{
int num_unassign = 0;
int i, j;
for (i = 0; i < SIZE; i++)
{
for (j = 0; j < SIZE; j++)
{
if (matrix[i][j] == 0)
{
*row = i;
*col = j;
num_unassign = 1;
return num_unassign;
}
}
}
return num_unassign;
}
int is_safe(int n, int r, int c)
{
int i;
for (i = 0; i < SIZE; i++)
{
if (matrix[r][i] == n)
return 0;
}
for (i = 0; i < SIZE; i++)
{
if (matrix[i][c] == n)
return 0;
}
return 1;
}
int solve_sudoku()
{
int row;
int col;
if (number_unassigned(&row, &col) == 0)
return 1;
int i;
for (i = 1; i <= SIZE; i++)
{
if (is_safe(i, row, col))
{
matrix[row][col] = i;
if (solve_sudoku())
return 1;
matrix[row][col] = 0;
}
}
return 0;
}
int** ReadSoduko(int n) {
int** matrix = (int**)malloc((sizeof(int*)) * n);
for (int i = 0; i < n; ++i) {
matrix[i] = (int*) malloc(sizeof(int) * n);
}
printf("\nEnter your soduko board:\n");
for (int i = 0; i < n; ++i) {
printf("Enter row [%d]: ", i);
for (int j = 0; j < n; ++j) {
scanf("%d", &matrix[i][j]);
}
}
return matrix;
}
int main()
{
printf("Size of matrix: "); //added this
scanf("%d", &SIZE); //added this
matrix = ReadSoduko(SIZE); //added this
if (solve_sudoku())
print_sudoku();
else
printf("No solution!\n");
return 0;
}
And don't forget that the matrix that you have declared statically doesn't have a solution, I have tested the same matrix, just replacing the 2 in first line by a 0
and it worked here.并且不要忘记您静态声明的矩阵没有解决方案,我已经测试了相同的矩阵,只是
replacing the 2 in first line by a 0
并且它在这里工作。
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