|시간 제한||메모리 제한||제출||정답||맞은 사람||정답 비율|
|2 초||512 MB||15||4||4||57.143%|
You are working on a new graphics system, which has added a new feature. Whenever you draw a figure, all the pixels in that figure flip from white to black, or from black to white. This image is what happens when three overlapping rectangles are drawn on a white field:
Starting with a white field, given a series of axis-aligned rectangles, how many pixels end up black?
Each input will consist of a single test case. Note that your program may be run multiple times on different inputs.
Each test case will begin with a line with a single integer n (1 ≤ n ≤ 100,000) indicating the number of rectangles.
Each of the next n lines will have four space-separated integers x1, y1, x2 and y2 (0 ≤ x1 < x2 ≤ 109, 0 ≤ y1 < y2 ≤ 109) which represent opposite corners of a rectangle. The rectangle consists of all pixels (x,y) such that x1 ≤ x < x2 and y1 ≤ y < y2, so the area of the rectangle is (x2 - x1) × (y2 - y1) pixels.
Output a single integer, which is the number of pixels that are black after all of the rectangles are drawn on a white field.
2 0 0 4 4 1 1 3 3
4 0 0 10 10 1 1 11 11 2 2 12 12 3 3 13 13