leetcode-598-Range-Addition-II

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描述

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:

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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.

分析

在最小数字组成的边界中的数字才会被每次更新，因此只要找到横坐标，纵坐标中的最小数字而已。

解决方案1(Java)

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class Solution {
    public int maxCount(int m, int n, int[][] ops) {
        for (int[] op: ops) {
            m = Math.min(m, op[0]);
            n = Math.min(n, op[1]);
        }
        return m*n;
    }
}

相关问题

(M) Range Addition

题目来源