Set Matrix Zeroes

/*
M-1: take two array one is of row size and other for columns size of matrix and initialise with -1.
     traverse the whole matrix and if any (i,j)=0 then make row_array[i]=0 and col_array[j]=0;
     Now we know which array should be 0 and which column should be 0.
     Traverse the row_array and make whole row for the matrix as 0 and same for column array.
     But this approach take O(m+n) size.

M-2: We will create row_array and col_array inside the matrix.
     We will find the first 0 in the matrix eg (r,c) so we will use whole rth row as column array
     and cth column as row array.
     One catch is there,It is 100% sure that rth row and cth column will be all 0 so we will fill
     that row and column at end otherwise it will create mess.



*/

class Solution {
public:
    void setZeroes(vector<vector<int>>& matrix) {
       int r=-1,c=-1;
       for(int i=0;i<matrix.size();i++){       //finding first 0 location and deciding row_arr and col_arr
           for(int j=0;j<matrix[0].size();j++){
               if(matrix[i][j]==0){r=i;c=j;break;}
           }
       }
       if(r==-1) return;
       for(int i=0;i<matrix.size();i++){     //selecting rows and column to be 0
           for(int j=0;j<matrix[0].size();j++){
               if(i==r && j==c) continue;
               if(matrix[i][j]==0){matrix[i][c]=0; matrix[r][j]=0;}
           }
       }
       for(int i=0;i<matrix.size();i++){  //making selected columns as 0.
           if(i==r) continue;
           if(matrix[i][c]==0){ for(int j=0;j<matrix[0].size();j++) matrix[i][j]=0; }
       }
       for(int j=0;j<matrix[0].size();j++){  //making selected rows as 0.
           if(j==c) continue;
           if(matrix[r][j]==0){ for(int i=0;i<matrix.size();i++) matrix[i][j]=0; }
       }
       for(int i=0;i<matrix.size();i++){     //making whole row_arr and col_arr as 0.
           for(int j=0;j<matrix[0].size();j++){
               if(i==r || j==c) matrix[i][j]=0;
           }
       }

    }
};