Given an m * n matrix M initialized with all 0’s and several update operations.

Operations are represented by a 2D array, and each operation is represented by an array with two positive integers a and b, which means M[i][j] should be added by one for all 0 <= i < a and 0 <= j < b.

You need to count and return the number of maximum integers in the matrix after performing all the operations.

Example 1:

``````Input:
m = 3, n = 3
operations = [[2,2],[3,3]]
Output: 4
Explanation:
Initially, M =
[[0, 0, 0],
[0, 0, 0],
[0, 0, 0]]

After performing [2,2], M =
[[1, 1, 0],
[1, 1, 0],
[0, 0, 0]]

After performing [3,3], M =
[[2, 2, 1],
[2, 2, 1],
[1, 1, 1]]

So the maximum integer in M is 2, and there are four of it in M. So return 4.
``````

Note:

1. The range of m and n is [1,40000].
2. The range of a is [1,m], and the range of b is [1,n].
3. The range of operations size won’t exceed 10,000.

``````class Solution {
public:
int maxCount(int m, int n, vector<vector<int>>& ops) {
if (ops.empty() || ops[0].empty()) return m * n;
priority_queue<int> r, c;
for (auto op : ops) {
r.push(-op[0]);
c.push(-op[1]);
}
return r.top() * c.top();
}
};
``````

``````class Solution {
public:
int maxCount(int m, int n, vector<vector<int>>& ops) {
for (auto op : ops) {
m = min(m, op[0]);
n = min(n, op[1]);
}
return m * n;
}
};
``````

Github 同步地址:

https://github.com/grandyang/leetcode/issues/598