N-Queen's Problem

Program's_Contributed_By_Contributors/Java_Programs/Data_structure/nQueen.java

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+//N-Queens with Normal Array and Inputs
+
+import java.util.Scanner;
+public class nQueen {
+
+  public static void display(int[][] mat,int N) {
+    for(int i=0;i<N;i++) {
+      for(int j=0;j<N;j++) {
+        System.out.print(mat[i][j]+", ");
+      }
+      System.out.println();
+    }
+    System.out.println("GAP");
+  }
+
+  public static int issafe(int[][] mat,int row,int col,int N) {
+    int i,j;
+    for(j=col;j>=0;j--) {
+      if(mat[row][j]==1) {
+        return 0;
+      }
+    }
+
+    for(i=row,j=col;i>=0&&j>=0;i--,j--) {
+      if(mat[i][j]==1) {
+        return 0;
+      }
+    }
+    for(i=row,j=col;i<N-1&&j>=0;i++,j--) {
+      if(mat[i][j]==1) {
+        return 0;
+      }
+    }
+    return 1;
+  }
+
+  public static void solve(int[][] mat,int col,int N) {
+
+    if(col==N) {
+      display(mat,N);
+    }else {
+      int row=0;
+      for(row=0;row<N;row++) {
+        if(issafe(mat,row,col,N)==1) {
+          mat[row][col]=1;
+          solve(mat,col+1,N);
+          mat[row][col]=0;
+        }
+      }
+    }
+  }
+
+  public static void main(String [] args) {
+    Scanner sc=new Scanner(System.in);
+    int N=sc.nextInt();
+    int[][] mat=new int[N][N];
+    solve(mat,0,N);
+    sc.close();
+  }
+
+}
+//Contributed By Ashutosh Ray