Cells with Odd Values in a Matrix (1252)

09 Apr 2020 in Algoirthm

leetcode 1252번 문제 (java)

문제 내용

Given n and m which are the dimensions of a matrix initialized by zeros and given an array indices where indices[i] = [ri, ci]. For each pair of [ri, ci] you have to increment all cells in row ri and column ci by 1. Return the number of cells with odd values in the matrix after applying the increment to all indices.

=> 간단히 해석하면 ri, ci에 해당하는 행, 열 모두 1씩 증가 시킨다. return 값은 1씩 모두 증가시키고 난 뒤 행렬 안에 odd value counting 값 입니다.

• Example

  Input: n = 2, m = 3, indices = [[0,1],[1,1]]
  Output: 6
  Explanation: Initial matrix = [[0,0,0],[0,0,0]].
  After applying first increment it becomes [[1,2,1],[0,1,0]].
  The final matrix will be [[1,3,1],[1,3,1]] which contains 6 odd numbers.
  

  -Example 2

  Input: n = 2, m = 2, indices = [[1,1],[0,0]]
  Output: 0
  Explanation: Final matrix = [[2,2],[2,2]]. There is no odd number in the final matrix.
  

• 범위

  1 <= n <= 50
  1 <= m <= 50
  1 <= indices.length <= 100
  0 <= indices[i][0] < n
  0 <= indices[i][1] < m
  

내가 찬 코드

class Solution {
    public int oddCells(int n, int m, int[][] indices) {
        
    int[][] array = new int[n][m];

    for(int[] k : indices){
      for(int i = 0; i <m; i++){
        array[k[0]][i]++;
      }
      for(int j =0; j<n;j++){
        array[j][k[1]]++;
      }
    }
    int count = 0;

    for(int i = 0 ; i <n; i++){
      for(int j = 0 ; j <m;j++){
        if(array[i][j]%2 == 1){
          count++;
        }
      }
    }
    return count;
    }
}