N Queen Problem (Data Structures and Algorithms #9)(Recursion #6)(Backtracking #5)

This video explains how to solve N Queen Problem by using backtracking in recursion.

[rishabhshukla]

great work sir. You have cleared my lots of doubt of the backtracking. Please add videos based on the dynamic programming.

[mallikarjunpidaparthi]

Excellent explanation brother all my backtracking doubts are clear now

[ektadhobley]

Love it, please keep making more videos! If possible on DP too!

[arunrnambiar]

Best Resource to understand Backtracking.Please add video fro Sudoku as well.

[arpitasood]

By far the best video on this problem. Kudos /\

[russianharrypotter]

I replaced "if NQueen(board, size, rowNew)) {return true}" with 'NQueen(board, size, rowNew)' and got all possible solutions :)

[HIMANSHUSHARMA-ehwv]

Awesome video like others...
Sir need some more problems using recursion to others data structures like Tree, linkedlist etc (:

[mayankkandpal]

Nice video sir,
sir please make video on how to switch career from companies like infosys, wipro, tcs, etc to product based companies.

[chitranjanjangid]

Python code for the same:

'''
N Queen Problem
'''

def IFvalidCell(board, rowNew, colNew, size):
valid = True
for i in range(size):
if board[i][colNew]:
valid = False
for i, j in zip(range(rowNew, -1, -1), range(colNew, -1, -1)):
if board[i][j]:
valid = False
for i, j in zip(range(rowNew, -1, -1), range(colNew, size)):
if board[i][j]:
valid = False
return valid

def NQueen(board, size, row):
if row == size-1:
for i in range(size):
for j in range(size):
print(board[i][j], end=" ")
print("\n")
return True
else:
for col in range(size):
rowNew = row + 1
if IFvalidCell(board, rowNew, col, size):
board[rowNew][col]=True
if(NQueen(board, size, rowNew)):
return True
board[rowNew][col]=False
return False


if __name__ == "__main__":
board = [[False, False, False, False],
[False, False, False, False],
[False, False, False, False],
[False, False, False, False]]
NQueen(board, 4, -1)