DP/最短路 URAL 1741 Communication Fiend

题目传送门

 /*
     题意：程序从1到n版本升级，正版+正版->正版，正版+盗版->盗版，盗版+盗版->盗版
             正版+破解版->正版，盗版+破解版->盗版
     DP：每种情况考虑一遍，递推就行了
     注意：开long long
 */
 #include <cstdio>
 #include <iostream>
 #include <algorithm>
 #include <cstring>
 #include <cmath>
 using namespace std;

 const int MAXN = 1e4 + ;
 const int INF = 0x3f3f3f3f;
 struct Node
 {
     int u, v, w;
     char s[];
 }node[MAXN];
 long long dp[MAXN][];

 bool cmp(Node x, Node y)
 {
     if (x.u == y.u)    return     x.v < y.v;
     return x.u < y.u;
 }

 int main(void)        //URAL 1741 Communication Fiend
 {
     //freopen ("T.in", "r", stdin);

     int n, m;
     while (scanf ("%d%d", &n, &m) == )
     {
         for (int i=; i<=m; ++i)
         {
             scanf ("%d %d %d %s", &node[i].u, &node[i].v, &node[i].w, &node[i].s);
         }
         sort (node+, node++m, cmp);

         memset (dp, -, sizeof (dp));
         dp[][] = ;
         for (int i=; i<=m; ++i)
         {
             Node a = node[i];
             if (a.s[] == 'L')
             {
                 if (dp[a.u][] != - && (dp[a.v][] == - || dp[a.v][] > dp[a.u][] + a.w))
                 {
                     dp[a.v][] = dp[a.u][] + a.w;
                 }
             }
             else if (a.s[] == 'P')
             {
                 if (dp[a.u][] != - && (dp[a.v][] == - || dp[a.v][] > dp[a.u][] + a.w))
                 {
                     dp[a.v][] = dp[a.u][] + a.w;
                 }
                 if (dp[a.u][] != - && (dp[a.v][] == - || dp[a.v][] > dp[a.u][] + a.w))
                 {
                     dp[a.v][] = dp[a.u][] + a.w;
                 }
             }
             else if (a.s[] == 'C')
             {
                 if (dp[a.u][] != - && (dp[a.v][] == - || dp[a.v][] > dp[a.u][] + a.w))
                 {
                     dp[a.v][] = dp[a.u][] + a.w;
                 }
                 if (dp[a.u][] != - && (dp[a.v][] == - || dp[a.v][] > dp[a.u][] + a.w))
                 {
                     dp[a.v][] = dp[a.u][] + a.w;
                 }
             }
         }

         if (dp[n][] == - && dp[n][] == -)    puts ("Offline");
         else
         {
             puts ("Online");
             if (dp[n][] == -)    printf ("%I64d\n", dp[n][]);
             else if (dp[n][] == -)    printf ("%I64d\n", dp[n][]);
             else    printf ("%I64d\n", min (dp[n][], dp[n][]));
         }
     }

     return ;
 }

 /*
 Online
 Offline
 */

 /*
     WA了4，5发，第一是抄Kuangbin的模板抄错了；第二是选取的INF值太小了
     以后学习一下最值的选取的方法:)
 */
 #include <cstdio>
 #include <iostream>
 #include <algorithm>
 #include <cstring>
 #include <vector>
 #include <cmath>
 #include <queue>
 using namespace std;

 const int MAXN = 1e4 + ;
 const int INF = 0x3f3f3f3f;
 const int INFF = 0x7fffffff;
 const long long inf = ((long long)<<);
 struct Edge
 {
     int v, w;
     int f;
     Edge (int _v = , int _w = , int _f = ) : v (_v), w (_w), f (_f) {}
 };
 bool vis[MAXN];
 int cnt[MAXN];
 long long d[MAXN][];
 vector<Edge> G[MAXN];
 int n, m;

 void add_edge(int u, int v, int w, int f)
 {
     G[u].push_back (Edge (v, w, f));
 }

 bool SPFA(int s)
 {
     memset (cnt, , sizeof (cnt));
     memset (vis, false, sizeof (vis));
     for (int i=; i<=n; ++i)    d[i][] = d[i][] = inf;
     vis[s] = true;    d[s][] = ;    cnt[s] = ;

     queue<int> Q;    Q.push (s);
     while (!Q.empty ())
     {
         int u = Q.front ();    Q.pop ();
         vis[u] = false;                        //失误！
         for (int i=; i<G[u].size (); ++i)
         {
             int v = G[u][i].v;    int w = G[u][i].w;    int f = G[u][i].f;
             if (f == )
             {
                 if (d[v][] > d[u][] + w)    d[v][] = d[u][] + w;
             }
             else if (f == )
             {
                 if (d[v][] > d[u][] + w)    d[v][] = d[u][] + w;
                 if (d[v][] > d[u][] + w)    d[v][] = d[u][] + w;
             }
             else
             {
                 if (d[v][] > d[u][] + w)    d[v][] = d[u][] + w;
                 if (d[v][] > d[u][] + w)    d[v][] = d[u][] + w;
             }
             if (!vis[v])
             {
                 vis[v] = true;    Q.push (v);
                 if (++cnt[v] > n)    return true;
             }
         }
     }

     return false;
 }

 int main(void)        //URAL 1741 Communication Fiend
 {
     //freopen ("T.in", "r", stdin);

     while (scanf ("%d%d", &n, &m) == )
     {
         for (int i=; i<=n; ++i)    G[i].clear ();
         for (int i=; i<=m; ++i)
         {
             int u, v, w, f;    char s[];
             scanf ("%d %d %d %s", &u, &v, &w, &s);
             if (s[] == 'L')    f = ;
             else if (s[] == 'P')    f = ;
             else if (s[] == 'C')    f = -;
             add_edge (u, v, w, f);
         }

         if (!SPFA ())
         {
             long long ans = min (d[n][], d[n][]);
             if (ans == inf)    puts ("Offline");
             else    {puts ("Online");    printf ("%I64d\n", ans);}
         }
     }

     return ;
 }

 /*
 Online
 Offline
 */

SPFA