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AiTechWorlds
AiTechWorlds
Animate the N-Queens backtracking solver placing queens row by row and backtracking on conflicts, with synced code.
def solve(row, n, cols, d1, d2, board):
if row == n:
return True
for c in range(n):
if c in cols or (row-c) in d1 or (row+c) in d2:
continue
cols.add(c); d1.add(row-c); d2.add(row+c)
if solve(row+1, n, cols, d1, d2, board):
return True
cols.discard(c); d1.discard(row-c); d2.discard(row+c)
return FalseThe N-Queens problem places N queens on an N×N board so that none attack each other. Backtracking tries each column per row, undoing a placement when it leads to a conflict.
| Time (worst) | O(n!) |
| Space | O(n) |
The N-Queens Visualizer animates how backtracking solves the N-Queens problem: it places one queen per row, trying each column, and backtracks whenever a queen would be attacked along a column or diagonal. Solving N-Queens is O(n!) in the worst case. Watch each try, placement, and backtrack with a live decision counter.
Press Play
Watch queens placed row by row; conflicts trigger a backtrack.
Step through
Use Step Forward/Back or the timeline to study each decision.
Read the code
View the N-Queens backtracking code in C++, Java, Python, or JavaScript and copy it.
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Last reviewed on June 14, 2026 by the AiTechWorlds Tools Team. All processing runs locally in your browser.