CSU 1333 Funny Car Racing

最短路问题稍微复杂了一点，松弛的时候多判断一些条件就可以了。第一次用SPFA写最短路。

 

 

#include<cstdio>

#include<cmath>

#include<cstring>

#include<vector>

#include<queue>

#include<algorithm>

using namespace std;



const int maxn = 305;

vector<int> cost[maxn][maxn];

vector<int> ljb[maxn];

struct abc{ int start, end, aa, bb, cc; }dt[50005];

int flag[maxn], dist[maxn];

int n, m, sx, ex;



void spfa()

{

    int i, ii; flag[sx] = 1;

    for (i = 0; i <= n; i++) dist[i] = 0x7FFFFFFF;

    dist[sx] = 0;

    queue<int>Q; Q.push(sx);

    while (!Q.empty())

    {

        int hh = Q.front(); Q.pop(); flag[hh] = 0;

        int nowtime = dist[hh];

        for (ii = 0; ii < ljb[hh].size(); ii++)

        {

            for (i = 0; i < cost[hh][ljb[hh][ii]].size(); i++)

            {

                int id = cost[hh][ljb[hh][ii]][i];

                if (dt[id].aa < dt[id].cc) continue;

                int yy = nowtime % (dt[id].aa + dt[id].bb);

                if (yy <= dt[id].aa)

                {

                    if (yy + dt[id].cc <= dt[id].aa)

                    {

                        if (nowtime + dt[id].cc < dist[ljb[hh][ii]])

                        {

                            dist[ljb[hh][ii]] = nowtime + dt[id].cc;

                            if (!flag[ljb[hh][ii]])Q.push(ljb[hh][ii]), flag[ljb[hh][ii]] = 1;

                        }

                    }

                    else

                    {

                        if (nowtime + dt[id].aa - yy + dt[id].bb + dt[id].cc < dist[ljb[hh][ii]])

                        {

                            dist[ljb[hh][ii]] = nowtime + dt[id].aa - yy + dt[id].bb + dt[id].cc;

                            if (!flag[ljb[hh][ii]])Q.push(ljb[hh][ii]), flag[ljb[hh][ii]] = 1;

                        }

                    }

                }

                else

                {

                    if (nowtime + dt[id].aa + dt[id].bb - yy + dt[id].cc< dist[ljb[hh][ii]])

                    {

                        dist[ljb[hh][ii]] = nowtime + dt[id].aa + dt[id].bb - yy + dt[id].cc;

                        if (!flag[ljb[hh][ii]])Q.push(ljb[hh][ii]), flag[ljb[hh][ii]] = 1;

                    }

                }

            }

        }

    }

}



int main()

{

    int _ = 1;

    int i, j, u, v, a, b, c;

    while (~scanf("%d%d%d%d", &n, &m, &sx, &ex))

    {

        for (i = 0; i <= n; i++) ljb[i].clear();

        for (i = 0; i <= n; i++) for (j = 0; j <= n; j++) cost[i][j].clear();

        memset(flag, 0, sizeof(flag));

        for (i = 0; i < m; i++)

        {

            scanf("%d%d%d%d%d", &u, &v, &a, &b, &c);

            dt[i].start = u; dt[i].end = v;

            dt[i].cc = c; dt[i].aa = a; dt[i].bb = b;

            cost[u][v].push_back(i);

            ljb[u].push_back(v);

        }

        spfa();

        printf("Case %d: %d\n", _++, dist[ex]);

    }

    return 0;

}