poj3592Instantaneous Transference（tarjan+spfa)

http://poj.org/problem?id=3592提交了30多次了 受不了了 两份的代码基本上一样了 一个AC一个WA 木办法 贴份别人的吧 改得跟我得一样 人家能A  我是WA。。

强连通分量缩点 用spfa算出最长路 注意算强连通时加过的值就不再加了

  1 #include <cstdio>

  2 #include <cstring>

  3 #include <iostream>

  4 #include <vector>

  5 #include <queue>

  6 #include<stack>

  7 using namespace std;

  8 const int NN=1606;

  9 const int MM=1000000;

 10 const int INF=0x3fffffff;

 11 

 12 int n,m,w[NN],val[NN];

 13 char c[42][42];

 14 vector<int> adj[NN];

 15 

 16 struct Edge{

 17     int u,v,next;

 18 }edge[MM];

 19 int t,head[NN];

 20 void addedge(int u,int v)

 21 {

 22     edge[t].u=u;

 23     edge[t].v=v;

 24     edge[t].next=head[u];

 25     head[u]=t++;

 26 }

 27 

 28 int bcnt,top,depth,dfn[NN],low[NN],belong[NN],vis[NN],instack[NN];

 29 //bool instack[NN];

 30 stack<int>s;

 31 void init()

 32 {

 33     t=0;

 34     memset(head,-1,sizeof(head));

 35 }

 36 void tarjan(int u)

 37 {

 38     dfn[u]=low[u]=++depth;

 39     s.push(u);

 40     instack[u] = 1;

 41     int v;

 42     for (int i=head[u]; i!=-1; i=edge[i].next)

 43     {

 44         v=edge[i].v;

 45         if (!dfn[v])

 46         {

 47             tarjan(v);

 48             low[u]=min(low[u],low[v]);

 49         }

 50         else if (instack[v])

 51             low[u]=min(low[u],dfn[v]);

 52     }

 53     if (low[u]==dfn[u])

 54     {bcnt++;

 55         val[bcnt] = 0;

 56         adj[bcnt].clear();

 57         for(;;)

 58         {

 59             v=s.top();

 60             s.pop();

 61             belong[v]=bcnt;

 62             val[bcnt]+=w[v];instack[v] = 0;

 63             if(v==u)

 64             break;

 65         }

 66 

 67     }

 68 }

 69 int dis[NN];

 70 int lpfa(int S)

 71 {

 72     for (int i=1; i<=bcnt; i++) dis[i]=-INF;

 73     memset(vis,0,sizeof(vis));

 74     dis[S]=0;

 75     queue<int> q;

 76     q.push(S);

 77     while (!q.empty())

 78     {

 79         int u=q.front();

 80         vis[u]=0;

 81         q.pop();

 82         for (int i=0; i<adj[u].size(); i++)

 83         {

 84             int v=adj[u][i];

 85             if (dis[v]<dis[u]+val[v])

 86             {

 87                 dis[v]=dis[u]+val[v];

 88                 if (!vis[v])

 89                 {

 90                     vis[v]=1;

 91                     q.push(v);

 92                 }

 93             }

 94         }

 95     }

 96     int ret=0;

 97     for (int i=1; i<=bcnt; i++) if (dis[i]>ret) ret=dis[i];

 98     return ret+val[S];

 99 }

100 void find(int n)

101 {

102    memset(dfn,0,sizeof(dfn));

103    memset(instack,0,sizeof(instack));

104    memset(val,0,sizeof(val));

105    memset(low,0,sizeof(low));

106    bcnt=depth=0;

107    for(int i = 0 ; i < n ; i++)

108    if (!dfn[i]) tarjan(i);

109 }

110 int main()

111 {

112     int cas;

113     scanf("%d",&cas);

114     while (cas--)

115     {

116         scanf("%d%d",&n,&m);

117         for (int i=0; i<n; i++)

118         {

119             getchar();

120             for (int j=0; j<m; j++) c[i][j]=getchar();

121         }

122         init();

123         int x,y;

124         for (int i=0; i<n; i++)

125           for (int j=0; j<m; j++)

126           {

127               int u= i*m+j;

128               if (c[i][j]=='*')

129               {

130                   w[u]=0;

131                   scanf("%d%d",&x,&y);

132                   addedge(u,x*m+y);

133               }

134               else w[u]=c[i][j]-'0';

135               if (c[i][j]=='#') { w[u]=0; continue; }

136               if (i!=n-1 && c[i+1][j]!='#') addedge(u,u+m);

137               if (j!=m-1 && c[i][j+1]!='#') addedge(u,u+1);

138           }

139         find(n*m);

140         int u,v;

141         for (int i=0; i<t; i++)

142         {

143             u=edge[i].u; v=edge[i].v;

144             if (belong[u]!=belong[v]) adj[belong[u]].push_back(belong[v]);

145         }

146         printf("%d\n",lpfa(belong[0]));

147     }

148     return 0;

149 }

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