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;
}