947 - Most Stones Removed with Same Row or Column.

Medium

On a 2D plane, we place n stones at some integer coordinate points. Each coordinate point may have at most one stone.

A stone can be removed if it shares either the same row or the same column as another stone that has not been removed.

Given an array stones of length n where <code>stonesi = x_i, y_i</code> represents the location of the <code>i^th</code> stone, return the largest possible number of stones that can be removed.

Example 1:

Input: stones = [0,0,0,1,1,0,1,2,2,1,2,2]

Output: 5

Explanation: One way to remove 5 stones is as follows:

• Remove stone 2,2 because it shares the same row as 2,1.

• Remove stone 2,1 because it shares the same column as 0,1.

• Remove stone 1,2 because it shares the same row as 1,0.

• Remove stone 1,0 because it shares the same column as 0,0.

• Remove stone 0,1 because it shares the same row as 0,0.

Stone 0,0 cannot be removed since it does not share a row/column with another stone still on the plane.

Example 2:

Input: stones = [0,0,0,2,1,1,2,0,2,2]

Output: 3

Explanation: One way to make 3 moves is as follows:

• Remove stone 2,2 because it shares the same row as 2,0.

• Remove stone 2,0 because it shares the same column as 0,0.

• Remove stone 0,2 because it shares the same row as 0,0.

Stones 0,0 and 1,1 cannot be removed since they do not share a row/column with another stone still on the plane.

Example 3:

Input: stones = [0,0]

Output: 0

Explanation: 0,0 is the only stone on the plane, so you cannot remove it.

Constraints:

• 1 <= stones.length <= 1000

• <code>0 <= x_i, y_i<= 10⁴</code>

• No two stones are at the same coordinate point.