最大流模板

Dinic模板:

HDU 4280

C++ 加了栈还是TLE ,然后手写对了快了三秒

  1 //#pragma comment(linker, "/STACK:1024000000,1024000000")
  2 #include <stdio.h>
  3 #include <algorithm>
  4 #include <string.h>
  5 #include <iostream>
  6 #include <string>
  7 #include <queue>
  8 #include<string.h>
  9 
 10 using namespace std;
 11 
 12 #define N 100010
 13 #define inf 0x3f3f3f3f
 14 
 15 struct edge
 16 {
 17   int next,v,c;
 18 }e[N<<1];
 19 int n,m;
 20 int tot,head[N],d[N];
 21 int q[N];
 22 
 23 int min(int a,int b)
 24 {
 25    return a<b?a:b;
 26 }
 27 
 28 void add(int u,int v,int c)
 29 {
 30  e[tot].v=v;e[tot].c=c;
 31  e[tot].next=head[u];head[u]=tot++;
 32 
 33  e[tot].v=u;e[tot].c=c;
 34  e[tot].next=head[v];head[v]=tot++;
 35 }
 36 
 37 int  bfs(int s,int t)
 38 {
 39    memset(d,-1,sizeof(d));
 40    int f=0,r=0;
 41    q[r++]=s;
 42    d[s]=0;
 43    
 44    while (f<r)
 45    {
 46          int u=q[f++];
 47          if (u==t) return 1;
 48          for (int i=head[u];i!=-1;i=e[i].next)
 49          {
 50            int v=e[i].v;
 51            if (d[v]==-1&&e[i].c>0)
 52            {
 53              d[v]=d[u]+1;
 54              q[r++]=v;
 55            }
 56          }
 57    }
 58    return 0;
 59 }
 60 
 61 int dfs(int s,int t,int b)
 62 {
 63   int r=0;
 64   if (s==t) return b;
 65   for (int i=head[s];i!=-1&&r<b;i=e[i].next)
 66   {
 67      int v=e[i].v;
 68      if (e[i].c>0&&d[v]==d[s]+1)
 69      {
 70        int x=min(e[i].c,b-r);
 71        x=dfs(v,t,x);
 72        r+=x;
 73        e[i].c-=x;
 74        e[i^1].c+=x;
 75      }
 76   }
 77   if (!r) d[s]-=2;
 78   return r;
 79 }
 80 
 81 int dinic(int s,int t)
 82 {
 83   int ans=0,tmp;
 84   while (bfs(s,t))
 85   {
 86      while (tmp=dfs(s,t,inf)) ans+=tmp;
 87   }
 88   return ans;
 89 }
 90 
 91 int main()
 92 {
 93    int T;
 94    scanf("%d",&T);
 95    while (T--)
 96    {
 97        memset(head,-1,sizeof(head));
 98        tot=0;
 99        int s,t;
100        scanf("%d%d",&n,&m);
101        int xx=-inf,yy=inf;
102        for (int i=1;i<=n;i++)
103        {
104           int x,y;
105           scanf("%d%d",&x,&y);
106           if (xx<x) xx=x,t=i;
107           if (yy>x) yy=x,s=i;
108        }
109 
110        while (m--)
111        {
112           int x,y,c;
113           scanf("%d%d%d",&x,&y,&c);
114           add(x,y,c);
115        }
116 
117        printf("%d\n",dinic(s,t));
118        }
119        return 0;
120 }
View Code

 

于是乎找来Sap 模板:

  1 #include<stdio.h>
  2 #include<string.h>
  3 #include<algorithm>
  4 #include<iostream>
  5 using namespace std;
  6 
  7 const int MAXN=100010;//点数的最大值
  8 const int MAXM=400010;//边数的最大值
  9 const int INF=0x3f3f3f3f;
 10 
 11 struct Node
 12 {
 13     int from,to,next;
 14     int cap;
 15 }edge[MAXM];
 16 int tol;
 17 int head[MAXN];
 18 int dep[MAXN];
 19 int gap[MAXN];//gap[x]=y :说明残留网络中dep[i]==x的个数为y
 20 
 21 int n;//n是总的点的个数,包括源点和汇点
 22 
 23 void init()
 24 {
 25     tol=0;
 26     memset(head,-1,sizeof(head));
 27 }
 28 
 29 void add_edge(int u,int v,int w)
 30 {
 31     edge[tol].from=u;
 32     edge[tol].to=v;
 33     edge[tol].cap=w;
 34     edge[tol].next=head[u];
 35     head[u]=tol++;
 36     edge[tol].from=v;
 37     edge[tol].to=u;
 38     edge[tol].cap=w;
 39     edge[tol].next=head[v];
 40     head[v]=tol++;
 41 }
 42 void BFS(int start,int end)
 43 {
 44     memset(dep,-1,sizeof(dep));
 45     memset(gap,0,sizeof(gap));
 46     gap[0]=1;
 47     int que[MAXN];
 48     int front,rear;
 49     front=rear=0;
 50     dep[end]=0;
 51     que[rear++]=end;
 52     while(front!=rear)
 53     {
 54         int u=que[front++];
 55         if(front==MAXN)front=0;
 56         for(int i=head[u];i!=-1;i=edge[i].next)
 57         {
 58             int v=edge[i].to;
 59             if(dep[v]!=-1)continue;
 60             que[rear++]=v;
 61             if(rear==MAXN)rear=0;
 62             dep[v]=dep[u]+1;
 63             ++gap[dep[v]];
 64         }
 65     }
 66 }
 67 int SAP(int start,int end)
 68 {
 69     int res=0;
 70     BFS(start,end);
 71     int cur[MAXN];
 72     int S[MAXN];
 73     int top=0;
 74     memcpy(cur,head,sizeof(head));
 75     int u=start;
 76     int i;
 77     while(dep[start]<n)
 78     {
 79         if(u==end)
 80         {
 81             int temp=INF;
 82             int inser;
 83             for(i=0;i<top;i++)
 84                if(temp>edge[S[i]].cap)
 85                {
 86                    temp=edge[S[i]].cap;
 87                    inser=i;
 88                }
 89             for(i=0;i<top;i++)
 90             {
 91                 edge[S[i]].cap-=temp;
 92                 edge[S[i]^1].cap+=temp;
 93             }
 94             res+=temp;
 95             top=inser;
 96             u=edge[S[top]].from;
 97         }
 98         if(u!=end&&gap[dep[u]-1]==0)//出现断层,无增广路
 99           break;
100         for(i=cur[u];i!=-1;i=edge[i].next)
101            if(edge[i].cap!=0&&dep[u]==dep[edge[i].to]+1)
102              break;
103         if(i!=-1)
104         {
105             cur[u]=i;
106             S[top++]=i;
107             u=edge[i].to;
108         }
109         else
110         {
111             int min=n;
112             for(i=head[u];i!=-1;i=edge[i].next)
113             {
114                 if(edge[i].cap==0)continue;
115                 if(min>dep[edge[i].to])
116                 {
117                     min=dep[edge[i].to];
118                     cur[u]=i;
119                 }
120             }
121             --gap[dep[u]];
122             dep[u]=min+1;
123             ++gap[dep[u]];
124             if(u!=start)u=edge[S[--top]].from;
125         }
126     }
127     return res;
128 }
129 int main()
130 {
131     int cn;
132     int m;
133     cin>>cn;
134     int t1,t2,t3;
135     while(cn--)
136     {
137         int maxn = -INF;
138         int minn = INF;
139         int maxi;
140         int mini;
141         cin>>n>>m;
142         init();
143         for(int i=1; i<=n; i++)
144         {
145             scanf("%d %d", &t1, &t2);
146             if(maxn < t1)
147             {
148                 maxn = t1;
149                 maxi = i;
150             }
151             if(minn > t1)
152             {
153                 minn = t1;
154                 mini = i;
155             }
156         }
157         while(m--)
158         {
159             scanf("%d %d %d", &t1, &t2, &t3);
160             add_edge(t1, t2, t3);
161         }
162         printf("%d\n", SAP(mini, maxi));
163     }
164  return 0;
165 }
View Code

 

posted on 2015-04-07 21:36  forgot93  阅读(171)  评论(0编辑  收藏  举报

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