[Swift]LeetCode850. 矩形面积 II | Rectangle Area II

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We are given a list of (axis-aligned) rectangles.  Each rectangle[i] = [x1, y1, x2, y2] , where (x1, y1) are the coordinates of the bottom-left corner, and (x2, y2) are the coordinates of the top-right corner of the ith rectangle.

Find the total area covered by all rectanglesin the plane.  Since the answer may be too large, return it modulo 10^9 + 7.

Example 1:

Input: [[0,0,2,2],[1,0,2,3],[1,0,3,1]]
Output: 6
Explanation: As illustrated in the picture.

Example 2:

Input: [[0,0,1000000000,1000000000]]
Output: 49
Explanation: The answer is 10^18 modulo (10^9 + 7), which is (10^9)^2 = (-7)^2 = 49.

Note:

• 1 <= rectangles.length <= 200
• rectanges[i].length = 4
• 0 <= rectangles[i][j] <= 10^9
• The total area covered by all rectangles will never exceed 2^63 - 1 and thus will fit in a 64-bit signed integer.

---

我们给出了一个（轴对齐的）矩形列表 rectangles 。 对于 rectangle[i] = [x1, y1, x2, y2]，其中（x1，y1）是矩形 i 左下角的坐标，（x2，y2）是该矩形右上角的坐标。

找出平面中所有矩形叠加覆盖后的总面积。 由于答案可能太大，请返回它对 10 ^ 9 + 7 取模的结果。

示例 1：

输入：[[0,0,2,2],[1,0,2,3],[1,0,3,1]]
输出：6
解释：如图所示。

示例 2：

输入：[[0,0,1000000000,1000000000]]
输出：49
解释：答案是 10^18 对 (10^9 + 7) 取模的结果， 即 (10^9)^2 → (-7)^2 = 49 。

提示：

• 1 <= rectangles.length <= 200
• rectanges[i].length = 4
• 0 <= rectangles[i][j] <= 10^9
• 矩形叠加覆盖后的总面积不会超越 2^63 - 1 ，这意味着可以用一个 64 位有符号整数来保存面积结果。

---

Runtime: 120 ms

Memory Usage: 19.7 MB

class Solution {
    func rectangleArea(_ rectangles: [[Int]]) -> Int {
        var M:Int = 1000000007
        var data:[Point] = [Point]()
        for r in rectangles
        {
            data.append(Point(r[0], r[1], 1))
            data.append(Point(r[0], r[3], -1))
            data.append(Point(r[2], r[1], -1))
            data.append(Point(r[2], r[3], 1))
        }
        data.sort(by:{(a:Point,b:Point) -> Bool in
                     if a.x == b.x {return b.y <= a.y}
                     return a.x < b.x})
        var map:[Int:Int] = [Int:Int]()
        var preX:Int = -1
        var preY:Int = -1
        var result:Int = 0
        for i in 0..<data.count
        {
            var p:Point = data[i]
            map[p.y,default:0] += p.val
            if i == data.count - 1 || data[i + 1].x > p.x
            {
                if preX > -1
                {
                    result += (preY * (p.x - preX)) % M
                    result %= M
                }
                preY = calcY(map)
                preX = p.x
            }
        }
        return result
    }

    func calcY(_ p:[Int:Int]) -> Int
    {
        var result:Int = 0
        var pre:Int = -1
        var count:Int = 0
        var nums = Set(p.keys).sorted(by:<)
        for key in nums
        {
            if pre >= 0 && count > 0
            {
                result += key - pre
            }
            count += p[key,default:0]
            pre = key
        }
        return result
    }
}

class Point
{
    var x:Int 
    var y:Int 
    var val:Int
    init(_ x:Int,_ y:Int,_ val:Int)
    {
        self.x = x
        self.y = y
        self.val = val
    }
}