Download or execution of a small applet
("nQueens.exe", 31 kb), written in VB 5, expected to run under all Windows versions.
The program generates all solutions of the n Queens Problem (0 ≤ n ≤ 32): "Place n queens on a n x n chessboard, such that no queen attacks any other one." 

input n
 input for the board width n (0 ≤ n ≤ 32) 
fixed queens / last shown position
 the positions of certain queens may be prescribed (red). Input of j in column i means: a queen is placed in row j of column i of the board. Empty input leads to the lexicographically first solution. / The last shown position always will be displayed here. 
test 
user input has to be tested before computation can start. 
start/continue 
the computation starts or will be continued after interruption. 
break 
interrupts a running computation. 
next solution 
starts a search for the next solution, when a solution already has been found. 
reset 
deletes all in and output, returns the applet to its initial state. 
quit 
finishes program execution and closes the applet window. 
actual position 
display for the last computed position of queens. Number j in column i means: on the chessboard there is a queen in column i and row j. If the positions of n queens are shown, a solution is found. 
state 
indicates the actual state of the applet. 
solution number 
counts the number of solutions already found. 
© H.B. Meyer 
download or execute program "nQueens.exe" 
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