Special Positions in a Binary Matrix Easy

Given a rows x cols matrix mat, where mat[i][j] is either 0 or 1, return the number of special positions in mat.

A position (i,j) is called special if mat[i][j] == 1 and all other elements in row i and column j are 0 (rows and columns are 0-indexed).

Example 1:

Input: mat = [[1,0,0],
              [0,0,1],
              [1,0,0]]
Output: 1

Approach

Java

public class SpecialPositionsBinaryMatrix {
    public static void main(String[] args) {
        int mat[][] = { { 1, 0, 0 }, { 0, 0, 1 }, { 1, 0, 0 } };
        System.out.println(numSpecial(mat));
    }

    // function to count the special position in
    // binary matrix
    static int numSpecial(int[][] mat) {
        int n = mat.length;
        int m = mat[0].length;
        int cnt = 0;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < m; j++) {
                if (mat[i][j] == 1) {
                    int flag = 0;
                    for (int k = 0; k < m; k++) {
                        if (k != j) {
                            if (mat[i][k] != 0) {
                                flag = 1;
                                break;
                            }
                        }
                    }
                    if (flag == 0) {
                        for (int k = 0; k < n; k++) {
                            if (k != i) {
                                if (mat[k][j] != 0) {
                                    flag = 1;
                                    break;
                                }
                            }
                        }
                    }
                    if (flag == 0)
                        cnt++;
                }
            }
        }
        return cnt;
    }
}

C++

#include <bits/stdc++.h>
using namespace std;

//function to count the special position in
//binary matrix
int numSpecial(vector<vector<int>>& mat)
{
     int n=mat.size(),m=mat[0].size();
     int cnt=0;
     for(int i=0;i<n;i++)
     {
         for(int j=0;j<m;j++)
         {
             if(mat[i][j]==1)
             {
                 int flag=0;
                 for(int k=0;k<m;k++)
                 {
                     if(k!=j)
                     {
                         if(mat[i][k]!=0)
                         {
                             flag=1;
                             break;
                         }
                     }
                 }
                 if(flag==0)
                 {
                     for(int k=0;k<n;k++)
                     {
                         if(k!=i)
                         {
                             if(mat[k][j]!=0)
                             {
                                 flag=1;
                                 break;
                             }
                         }
                     }
                 }
                if(flag==0)
                      cnt++;
             }
         }
     }
        return cnt;
}
int main()
{
  vector<vector<int>> mat = {{1,0,0},
                             {0,0,1},
                             {1,0,0}};
  cout<<numSpecial(mat);
  return 0;
}