```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 ``` ```/* Description: Using Brute-Force to solve 8 Queens Problem Author: Liutong Xu Date: 2016/10/26 */ #include int main() { int a[8][8]; //a[i][j]==1 means a Queen on ij-th position int i,j,k; int isvalid; int i0,i1,i2,i3,i4,i5,i6,i7; int count = 0; //all possible solutions for (i0=0;i0<8;i0++) for (i1=0;i1<8;i1++) for (i2=0;i2<8;i2++) for (i3=0;i3<8;i3++) for (i4=0;i4<8;i4++) for (i5=0;i5<8;i5++) for (i6=0;i6<8;i6++) for (i7=0;i7<8;i7++) { for (i=0;i<8;i++) for (j=0;j<8;j++) a[i][j]=0; //erase old data a[0][i0]=1; //a queen on every row a[1][i1]=1; a[2][i2]=1; a[3][i3]=1; a[4][i4]=1; a[5][i5]=1; a[6][i6]=1; a[7][i7]=1; isvalid = 1; //possibly valid //testing for validity for (i=0;i<8 && isvalid;i++) for (j=0;j<8 && isvalid;j++) { for (k=1;k<8 && isvalid;k++) { if (a[i][j] * a[i+k][j] && i+k<8) isvalid = 0; //if (a[i][j] * a[i][j+k] && j+k<8) isvalid = 0; if (a[i][j] * a[i+k][j+k] && i+k<8 && j+k<8 ) isvalid = 0; if (a[i][j] * a[i-k][j+k] && i-k>=0 && j+k<8 ) isvalid = 0; } } //print out valid solution if (isvalid) { count++; //one more valid solution for (i=0;i<8;i++) { printf("\n|"); for (j=0;j<8;j++) if (a[i][j]) printf("Q|"); else printf(" |"); } printf("\n================="); } //next possible solution } printf("\nThere are %d solutions.\n",count); return 0; } ```
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