Set matrix Zeros.cpp

class Solution {
public:
    void setZeroes(vector<vector<int>>& matrix) {
        /*int col=1,r=matrix.size(),c=matrix[0].size();
        for(int i=1;i<r;i++){
            if(matrix[i][0]) col=0;
            for(int j=1;j<c;j++){
                if(matrix[i][j]==0){
                    matrix[i][0]= matrix[0][j]=0;
                }
            }
        }
        
        for(int i=r-1;i>=0;i--){
            for(int j=c-1;j>=1;j--)
                if(matrix[i][0]==0 || matrix[0][j]==0)
                    matrix[i][j]=0;
            if(col==0)matrix[i][0];
        }*/
        bool isCol = false;
    int R = matrix.size();
    int C = matrix[0].size();

    for (int i = 0; i < R; i++) {

      // Since first cell for both first row and first column is the same i.e. matrix[0][0]
      // We can use an additional variable for either the first row/column.
      // For this solution we are using an additional variable for the first column
      // and using matrix[0][0] for the first row.
      if (matrix[i][0] == 0) {
        isCol = true;
      }

      for (int j = 1; j < C; j++) {
        // If an element is zero, we set the first element of the corresponding row and column to 0
        if (matrix[i][j] == 0) {
          matrix[0][j] = 0;
          matrix[i][0] = 0;
        }
      }
    }

    // Iterate over the array once again and using the first row and first column, update the elements.
    for (int i = 1; i < R; i++) {
      for (int j = 1; j < C; j++) {
        if (matrix[i][0] == 0 || matrix[0][j] == 0) {
          matrix[i][j] = 0;
        }
      }
    }

    // See if the first row needs to be set to zero as well
    if (matrix[0][0] == 0) {
      for (int j = 0; j < C; j++) {
        matrix[0][j] = 0;
      }
    }

    // See if the first column needs to be set to zero as well
    if (isCol) {
      for (int i = 0; i < R; i++) {
        matrix[i][0] = 0;
      }
    }
        
    }
};