Create NQueen Problem.c

NQueen Problem.c

@@ -0,0 +1,77 @@
+#include<stdio.h>
+#include<conio.h>
+#include<math.h>
+int board[20],count;
+void queen(int row,int n);
+void main()
+{
+ int n,i,j;
+ clrscr();
+ printf("    N Queens Problem Using Backtracking  ");
+ printf("\nEnter the no of Queens:");
+ scanf("%d",&n);
+ queen(1,n);
+ getch();
+}
+void print(int n)
+{
+ int i,j;
+ printf("\n\nSolution %d:\n\n",++count);
+ for(i=1;i<=n;++i)
+ {
+  printf("\t%d",i);
+ }
+ for(i=1;i<=n;++i)
+ {
+  printf("\n\n%d",i);
+  for(j=1;j<=n;++j)
+  {
+   if(board[i]==j)
+   {
+    printf("\tQ");
+   }
+   else
+   {
+    printf("\n-");
+   }
+  }
+ }
+}
+int place(int row,int column)
+{
+ int i;
+ for(i=1;i<=row-1;++i)
+ {
+  if(board[i]==column)
+  {
+   return 0;
+  }
+  else
+  {
+   if(abs(board[i]-column)==abs(i-row))
+   {
+    return 0;
+   }
+  }
+ }
+ return 1;
+}
+void queen(int row,int n)
+{
+ int column;
+ for(column=1;column<=n;++column)
+ {
+  if(place(row,column))
+  {
+   board[row]=column;
+   if(row==n)
+   {
+    print(n);
+   }
+   else
+   {
+    queen(row+1,n);
+   }
+  }
+ }
+}