Cod sursa(job #772719)

Utilizator danalex97Dan H Alexandru danalex97 Data 30 iulie 2012 16:30:46
Problema Cc Scor 100
Compilator cpp Status done
Runda Arhiva de probleme Marime 1.57 kb
#include <cstring>
#include <fstream>
#include <algorithm>
#include <queue>

using namespace std;

const int oo = 0x3f3f3f3f;

int N, Cost[205][205];
int F[205][205], C[205][205];

queue<int> Q;

int Dist[205], Dad[205];
bool Incr[205];
int minC;

bool BellmanFord();

int main()
{
    ifstream In("cc.in");
    ofstream Out("cc.out");

    In >> N;
    for (int i = 1; i <= N; ++i)
        for (int j = 1, cost; j <= N; ++j)
        {
            In >> cost;

            Cost[i][N + j] = cost;
            Cost[N + j][i] = -cost;

            C[i][N + j] = 1;
        }
    for (int i = 1; i <= N; ++i)
    {
        C[0][i] = 1;
        C[N + i][2 * N + 1] = 1;
    }

    while (BellmanFord());

    Out << minC;

    In.close();
    Out.close();
}

bool BellmanFord()
{
    for (int i = 1; i <= 2 * N + 1; ++i)
        Dist[i] = oo;
    Dist[0] = 0;

    Q.push(0);
    while (!Q.empty())
    {
        int now = Q.front(); Q.pop();
        Incr[now] = false;

        for (int i = 1; i <= 2 * N + 1; ++i)
            if (F[now][i] < C[now][i] && Dist[now] + Cost[now][i] < Dist[i])
            {
                Dist[i] = Dist[now] + Cost[now][i];
                Dad[i] = now;

                if (!Incr[i])
                {
                    Incr[i] = true;
                    Q.push(i);
                }
            }
    }

    if (Dist[2 * N + 1] == oo) return false;

    for (int i = 2 * N + 1; i != 0; i = Dad[i])
        ++F[Dad[i]][i], --F[i][Dad[i]];
    minC += Dist[2 * N + 1];

    return true;
}