Is Tom's meadow beautiful now?

Beautiful Meadow

#include <fstream>
#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
//Is Tom's meadow beautiful now?
int main()
{
    //ifstream cin("beautiful_meadow.txt");
    int n,m;
    while(cin>>n>>m)
    {   
        bool b=true;
        if(n==0) break;
        vector<int>v;   //mowed squares
        for(int i=0;i<n;i++)
        {   
            for(int j=0;j<m;j++)
            {
                int c;
                cin>>c;
                if(c==0) v.push_back(i*10+j);   //1<<n,m<<10
            }   
        }   
        if(v.size()==0) //no mowed squares
            b=false;
        if(v.size()>1)  //more than one mowed squares
        {   
            vector<int>::iterator it; 
            for(int i=0;i<v.size();i++)
            {   
                int a[4]={v[i]-1,v[i]+1,v[i]+10,v[i]-10};   //adjacent squares
                for(int j=0;j<4;j++)
                {   
                    it=find(v.begin(),v.end(),a[j]);
                    if(*it>0)   //no two squares are adjacent
                    {   
                        b=false;
                        break;
                    }   
                }   
                if(!b) break;
            }   
        }   
        if(b) cout<<"Yes"<<endl;    //beautiful
        if(!b) cout<<"No"<<endl;    //not beautiful
    }   
    return 0;
}