(LightOj) 1221 – Travel Company

Bellman Ford can’t find a cycle if it’s not reachable from starting node. So, Floyd-Warshall is much safer option!

Never use INFINITY. If you add something with INFINITY it will overflow.

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#include<bits/stdc++.h>


#define FOR(i, s, e) for(int i=s; i<e; i++)
#define loop(i, n) FOR(i, 0, n)
#define sf scanf
#define pf printf
#define pb push_back
#define MP make_pair
#define fr first
#define sc second
#define ll long long
#define dd double
#define all(v) v.begin(), v.end()
#define PI acos(-1.0)
#define mem(ara, value) memset(ara, value, sizeof(ara))
#define paii pair<int, int>
#define pall pair<ll, ll>
#define SZ(a) int(a.size())
#define read(nm) freopen(nm, "r", stdin)
#define write(nm) freopen(nm, "w", stdout)

#define dump(x) cerr<<#x<<" = "<<x<<endl
#define debug(args...) cerr,args; cerr<<endl;
using namespace std;


template<typename T>
ostream& operator<<(ostream& output, vector<T>&v)
{
    output<<"[ ";
    if(SZ(v))
    {
        output<<v[0];
    }
    FOR(i, 1, SZ(v))
    {
        output<<", "<<v[i];
    }
    output<<" ]";
    return output;
}

template<typename T1, typename T2>
ostream& operator<<(ostream& output, pair<T1, T2>&p)
{
    output<<"( "<<p.fr<<", "<<p.sc<<" )";
    return output;
}




template<typename T>
ostream& operator,(ostream& output, T x)
{
    output<<x<<" ";
    return output;
}


#define take(args...) asdf,args
struct ASDF{
    ASDF& operator,(int &a) {
        sf("%d", &a);
        return *this;
    }
    ASDF& operator,(long int &a){
        sf("%ld", &a);
        return *this;
    }
    ASDF& operator,(long long int &a){
        sf("%lld", &a);
        return *this;
    }
    ASDF& operator,(char &c){
        sf("%c", &c);
        return *this;
    }
    ASDF& operator,(double &d){
        sf("%lf", &d);
        return *this;
    }

    template<typename T>
    ASDF& operator,(T &a){
        cin>>a;
        return *this;
    }
}asdf;


//Header ends here

#define MAXX 107


int N, R, P;

ll dist[MAXX][MAXX];



int main()
{
    //read("input");
    int kases, kaseno=0;

    ll u, v, income, expense;

    cin>>kases;

    while(kases--)
    {
        cin>>N>> R>> P;


        loop(i, MAXX)
        {
            loop(j, MAXX)
            {
                dist[i][j] = (1<<29);
            }
            dist[i][i] = 0;
        }


        loop(i, R)
        {
            cin>>u>> v>> income>> expense;
            dist[u][v] = P*expense - income;
        }


        bool negetiveCycle = false;

        loop(k, N)
        {
            loop(i, N)
            {
                loop(j, N)
                {
                    dist[i][j] = min(dist[i][j], dist[i][k] + dist[k][j]);
                }
            }
        }

        loop(i, N)
        {
            if(dist[i][i] < 0)
            {
                //dump(i);
                negetiveCycle = true;
                break;
            }
        }


        pf("Case %d: %s\n", ++kaseno, negetiveCycle?"YES":"NO");


    }



}

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