八皇后算法

/*

 

   2008.7.7 g++ 通过测试

 

*/

 

#include "stdio.h"
#include "stdlib.h"
#include "string.h"
 
#define ROWS 8
 

//代表8个皇后的位置
int queens[ROWS]; 
 

//递归算法，在某一行放入皇后
void fill(int);

//检测该位置是否符合要求
int checked(int, int);
void show_queens();
 
 
int main() {
        fill(0);
        return 0;
}

 

 

void fill(int rowindex) {
        for(int i=0; i                        if(checked(rowindex, i) == 1) {
                                queens[rowindex] = i;
                                if(rowindex == ROWS-1) {
                                        show_queens();
                                } else {
                                        fill(rowindex + 1);
                                }
                        } else {
                                continue;
                        }
        }
}
 
int checked(int rowindex, int value) {
//      printf("check %d %d\n", rowindex, value);
        if(rowindex == 0)return 1;
        for(int i=0; i                if(value == queens[i]) {
//                      printf("--------------------------------\n");
                        return 0;
                }
        }
        int tmpindex = rowindex;
        int tmp1,tmp2;
        tmp1 = tmp2 = value;
        while((--tmpindex) >= 0) {
                if((tmpindex >= 0 && tmpindex < ROWS) && (queens[tmpindex] == --tmp1 || queens[tmpindex] == ++tmp2)) {
//                      printf("++++++++++++++++++++++++++++++++++\n");
                        return 0;
                }
        }
        return 1;
}
 
void show_queens() {
        printf("queens:");
        for(int i=0; i                printf("%d\t", queens[i]);
        }
        printf("\n");
}