java-algorithms/NQueenProblem.java at main · Mahidhar05/java-algorithms · GitHub

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publicclassNQueenProblem {
finalintN = 4;


voidprintSolution(intboard[][])
	{
for (inti = 0; i < N; i++) {
for (intj = 0; j < N; j++)
System.out.print(" " + board[i][j]
 + " ");
System.out.println();
 }
	}


booleanisSafe(intboard[][], introw, intcol)
	{
inti, j;


for (i = 0; i < col; i++)
if (board[row][i] == 1)
returnfalse;

for (i = row, j = col; i >= 0 && j >= 0; i--, j--)
if (board[i][j] == 1)
returnfalse;

for (i = row, j = col; j >= 0 && i < N; i++, j--)
if (board[i][j] == 1)
returnfalse;

returntrue;
	}

booleansolveNQUtil(intboard[][], intcol)
	{

if (col >= N)
returntrue;

for (inti = 0; i < N; i++) {
if (isSafe(board, i, col)) {
board[i][col] = 1;
if (solveNQUtil(board, col + 1) == true)
returntrue;

board[i][col] = 0;
 }
 }
returnfalse;
	}

booleansolveNQ()
	{
intboard[][] = { { 0, 0, 0, 0 },
 { 0, 0, 0, 0 },
 { 0, 0, 0, 0 },
 { 0, 0, 0, 0 } };

if (solveNQUtil(board, 0) == false) {
System.out.print("Solution does not exist");
returnfalse;
 }

printSolution(board);
returntrue;
	}

publicstaticvoidmain(Stringargs[])
	{
NQueenProblemQueen = newNQueenProblem();
Queen.solveNQ();
	}
}