# 4. Cellsweeper

Given an *n X n* matrix, you need to find the maximum sum of the elements
of a selection such that a selection may contain only 1 element from each row
or column.

i.e. You may not select an element from a row or column if you have already selected an element that lies in that row or column.

Interactive Example: (reset)

1 | 8 | 6 | 25 |

15 | 7 | 8 | 3 |

9 | 30 | 2 | 8 |

5 | 6 | 20 | 4 |

Sum till now: 0