Given an array rectangles where rectangles[i] = [xi, yi, ai, bi] represents an axis-aligned rectangle. The bottom-left point of the rectangle is (xi, yi) and the top-right point of it is (ai, bi).
Return true if all the rectangles together form an exact cover of a rectangular region.
Example 1:
Input: rectangles = [[1,1,3,3],[3,1,4,2],[3,2,4,4],[1,3,2,4],[2,3,3,4]] Output: true Explanation: All 5 rectangles together form an exact cover of a rectangular region.
Example 2:
Input: rectangles = [[1,1,2,3],[1,3,2,4],[3,1,4,2],[3,2,4,4]] Output: false Explanation: Because there is a gap between the two rectangular regions.
Example 3:
Input: rectangles = [[1,1,3,3],[3,1,4,2],[1,3,2,4],[2,2,4,4]] Output: false Explanation: Because two of the rectangles overlap with each other.
Constraints:
1 <= rectangles.length <= 2 * 104rectangles[i].length == 4-105 <= xi, yi, ai, bi <= 105
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