1267. Count Servers that Communicate

Medium

You are given a map of a server center, represented as a m * n integer matrix grid, where 1 means that on that cell there is a server and 0 means that it is no server. Two servers are said to communicate if they are on the same row or on the same column.

Return the number of servers that communicate with any other server.

Example 1:

Input: grid = [[1,0],[0,1]]
Output: 0
Explanation: No servers can communicate with others.

Example 2:

Input: grid = [[1,0],[1,1]]
Output: 3
Explanation: All three servers can communicate with at least one other server.

Example 3:

Input: grid = [[1,1,0,0],[0,0,1,0],[0,0,1,0],[0,0,0,1]]
Output: 4
Explanation: The two servers in the first row can communicate with each other. The two servers in the third column can communicate with each other. The server at right bottom corner can't communicate with any other server.

Constraints:

m == grid.length
n == grid[i].length
1 <= m <= 250
1 <= n <= 250
grid[i][j] == 0 or 1

class Solution {
    public int countServers(int[][] grid) {
        int r = grid.length;
        int c = grid[0].length;
        int ro[] = new int[r];
        int co[] = new int [c];
        int res = 0;
            
        for(int i = 0; i < r; i++){
            for(int j = 0; j < c; j++){
                if(grid[i][j] == 1){
                    res++;
                    ro[i]++;
                    co[j]++;
                }
            }
        }
        for(int i = 0; i < r; i++){
            for(int j = 0; j < c; j++){
                if(grid[i][j] == 1 && ro[i] == 1 && co[j] == 1) res--;
            }
        }
        return res;
    }
}

https://leetcode.com/problems/count-servers-that-communicate/discuss/436188/Java-or-Clean-And-Simple-or-Beats-100

利用题目告诉的同一row，同一col就算communica即使没连着。

先统计总共有多少servers，以及每行每列的个数。

然后减去行列都只等于1的servers得到答案。