Hi,

I think there is some problem with erasing the iterator while iterating through the map..

The output of this code shows that the value of m.end() is not updated in the first for loop.

for(int i=0;i<n;i++)
{   int s,b;
    cin>>s>>b;
    m[s]=b;

}

int cnt=0; 
map<int,int>::iterator it,it2;
for(it=m.begin();it!=m.end();it++)
{   
    cout<<"it 1 "<<it->first<<" "<<it->second<<endl;

    for(it2=m.begin();it2!=m.end();it2++)
    {
        cout<<"it 2 "<<it2->first<<" "<<it2->second<<endl;
        if(it2->first<s)
        {   cnt++;
            s+=it2->second;
            m.erase(it2);
            break;
        }
    }
}

Input : 999 2

1010 10

67 89

Output: it 1 67 89

it 2 67 89

it 1 1330860869 1162633042

it 2 1010 10

also, I think m[s]+=b was what you were looking for :)