You are given an?m x n?matrix?M?initialized with all?0's and an array of operations?ops, where?ops[i] = [ai, bi]?means?M[x][y]?should be incremented by one for all?0 <= x < ai?and?0 <= y < bi.

Count and return?the number of maximum integers in the matrix after performing all the operations.

?

Example 1:

Input: m = 3, n = 3, ops = [[2,2],[3,3]]

Output: 4

Explanation: The maximum integer in M is 2, and there are four of it in M. So return 4.

Example 2:

Input: m = 3, n = 3,?

ops = [[2,2],[3,3],[3,3],[3,3],[2,2],[3,3],[3,3],[3,3],[2,2],[3,3],[3,3],[3,3]]

Output: 4

Example 3:

Input: m = 3, n = 3, ops = []

Output: 9

?

Constraints:

• 1 <= m, n <= 4 * 104

• 0 <= ops.length <= 104

• ops[i].length == 2

• 1 <= ai?<= m

• 1 <= bi?<= n

• 汗顏啊，寫了一大串，直接memory exceed，還是數(shù)學(xué)快啊。

Runtime:?0 ms, faster than?100.00%?of?Java?online submissions for?Range Addition II.

Memory Usage:?42.4 MB, less than?63.10%?of?Java?online submissions for?Range Addition II.