598. Range Addition II

1. Question

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

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

2. Examples

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

3. Constraints

• 1 <= m, n <= 4 * 10⁴
• 0 <= ops.length <= 10⁴
• ops[i].length == 2
• 1 <= a_i <= m
• 1 <= b_i <= n

4. References

来源：力扣（LeetCode） 链接：https://leetcode-cn.com/problems/range-addition-ii 著作权归领扣网络所有。商业转载请联系官方授权，非商业转载请注明出处。

5. Solutions

class Solution {
  public int maxCount(int m, int n, int[][] ops) {
    int a = Integer.MAX_VALUE;
    int b = Integer.MAX_VALUE;
    for (int i = 0; i < ops.length; i++) {
      for (int j = 0; j < 2; j++) {
        a = Math.min(a, ops[i][0]);
        b = Math.min(b, ops[i][1]);
      }
    }
    return ops.length == 0 ? m * n : a * b;
  }
}