BZOJ1266: [AHOI2006]上学路线route

  1 #include<cstdio>
  2  
  3 #include<cstdlib>
  4  
  5 #include<cmath>
  6  
  7 #include<cstring>
  8  
  9 #include<algorithm>
 10  
 11 #include<iostream>
 12  
 13 #include<vector>
 14  
 15 #include<map>
 16  
 17 #include<set>
 18  
 19 #include<queue>
 20  
 21 #include<string>
 22  
 23 #define inf 1000000000
 24  
 25 #define maxn 100000
 26  
 27 #define maxm 500000
 28  
 29 #define eps 1e-10
 30  
 31 #define ll long long
 32  
 33 #define pa pair<int,int>
 34  
 35 #define for0(i,n) for(int i=0;i<=(n);i++)
 36  
 37 #define for1(i,n) for(int i=1;i<=(n);i++)
 38  
 39 #define for2(i,x,y) for(int i=(x);i<=(y);i++)
 40  
 41 #define for3(i,x,y) for(int i=(x);i>=(y);i--)
 42  
 43 using namespace std;
 44  
 45 inline int read()
 46  
 47 {
 48  
 49     int x=0,f=1;char ch=getchar();
 50  
 51     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
 52  
 53     while(ch>=‘0‘&&ch<=‘9‘){x=10*x+ch-‘0‘;ch=getchar();}
 54  
 55     return x*f;
 56  
 57 }
 58 int  n,m,s,t,maxflow,tot=1,head[maxn],cur[maxn],h[maxn],q[maxm];
 59 int x[maxm],y[maxm],z[maxm],w[maxm],d[2][maxn];
 60  
 61 struct edge{int go,next,v;}e[2*maxm];
 62 bool v[maxn];
 63  
 64 void ins(int x,int y,int z){e[++tot].go=y;e[tot].v=z;e[tot].next=head[x];head[x]=tot;}
 65  
 66 void insert(int x,int y,int z){ins(x,y,z);ins(y,x,0);}
 67  
 68 bool bfs()
 69  
 70 {
 71  
 72     for(int i=s;i<=t;i++)h[i]=-1;
 73  
 74     int l=0,r=1;q[1]=s;h[s]=0;
 75  
 76     while(l<r)
 77  
 78     {
 79  
 80         int x=q[++l];
 81  
 82         for(int i=head[x];i;i=e[i].next)
 83  
 84          if(e[i].v&&h[e[i].go]==-1)
 85  
 86          {
 87  
 88             h[e[i].go]=h[x]+1;q[++r]=e[i].go;
 89  
 90          }
 91  
 92     }
 93  
 94     return h[t]!=-1;
 95  
 96 }
 97  
 98 int dfs(int x,int f)
 99  
100 {
101  
102     if(x==t) return f;
103  
104     int tmp,used=0;
105  
106     for(int i=head[x];i;i=e[i].next)
107  
108      if(e[i].v&&h[e[i].go]==h[x]+1)
109  
110     {
111  
112         tmp=dfs(e[i].go,min(e[i].v,f-used));
113  
114         e[i].v-=tmp;if(e[i].v)cur[x]=i;
115  
116         e[i^1].v+=tmp;used+=tmp;
117  
118         if(used==f)return f;       
119  
120     }
121  
122     if(!used) h[x]=-1;
123  
124     return used;
125  
126 }
127  
128 void dinic()
129  
130 {
131  
132     maxflow=0;
133  
134     while(bfs())
135  
136     {
137  
138         for (int i=s;i<=t;i++)cur[i]=head[i];maxflow+=dfs(s,inf);
139  
140     }
141  
142 }
143  
144 void spfa(int k)
145  
146 {
147  
148     for(int i=1;i<=n;++i) d[k][i]=inf;
149  
150     memset(v,0,sizeof(v));
151     s=k==0?1:n;
152  
153     int l=0,r=1,x;q[1]=s;d[k][s]=0;
154  
155     while(l<r)
156  
157     {
158  
159         x=q[++l];v[x]=0;
160  
161         for(int i=head[x],y;i;i=e[i].next)
162  
163          if(d[k][x]+e[i].v<d[k][y=e[i].go])
164  
165          {
166  
167             d[k][y]=d[k][x]+e[i].v;
168             
169  
170             if(!v[i]){v[i]=1;q[++r]=i;}
171  
172          }
173  
174     }
175  
176 }
177 inline void ins2(int x,int y,int z)
178 {
179    e[++tot].go=y;e[tot].v=z;e[tot].next=head[x];head[x]=tot;
180    e[++tot].go=x;e[tot].v=z;e[tot].next=head[y];head[y]=tot;
181 }
182 int main()
183  
184 {
185     freopen("input.txt","r",stdin);
186     freopen("output.txt","w",stdout);
187     n=read();m=read();
188     for1(i,m)
189      {
190          x[i]=read();y[i]=read();z[i]=read();w[i]=read();
191          ins2(x[i],y[i],z[i]);
192      }
193     spfa(0);spfa(1);
194     tot=1;
195     memset(head,0,sizeof(head));
196     for1(i,m)
197     {
198         if(d[0][x[i]]+z[i]+d[1][y[i]]==d[0][n])insert(x[i],y[i],w[i]);
199         if(d[0][y[i]]+z[i]+d[1][x[i]]==d[0][n])insert(y[i],x[i],w[i]);
200     }
201     s=0;t=n+1;
202     insert(s,1,inf);insert(n,t,inf);
203     dinic();
204     printf("%d\n",d[0][n]);
205     printf("%d\n",maxflow);
206  
207     return 0;
208  
209 }

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<algorithm>
 4 #define INF 2100000000
 5 #define N 1005
 6 #define M 250005
 7 using namespace std;
 8 struct arr{int go,c,next,s;}a[M];
 9 int map[N][N],dis[2][N],f[N],q[M*2],end[N];
10 bool flag[N];
11 int x,y,z,c,i,n,m,cnt,ans;
12 void add(int u,int v,int s,int w)
13 {
14   a[++cnt].go=v;a[cnt].c=w;a[cnt].s=s;a[cnt].next=end[u];
15   end[u]=cnt;
16 }
17 void SPFA(int o,int sta)
18 {
19   int h=0,t=1;q[1]=sta;
20   memset(flag,0,sizeof(flag));
21   dis[o][sta]=0;flag[sta]=true;
22   while (h<t)
23   {
24     int now=q[++h];
25     for (int i=end[now];i;i=a[i].next)
26     {
27       int go=a[i].go;
28       if (dis[o][now]+a[i].s<dis[o][go])
29       {
30         dis[o][go]=dis[o][now]+a[i].s;
31         if (!flag[go]) flag[go]=true,q[++t]=go;
32       }
33     }
34     flag[now]=false;
35   }
36 } 
37 void init()
38 {
39   for (int i=1;i<=n;i++)
40     for (int j=end[i];j;j=a[j].next)
41       if (dis[0][i]+a[j].s+dis[1][a[j].go]==dis[0][n])
42         map[i][a[j].go]+=a[j].c;
43 }
44 bool bfs()
45 {
46   memset(f,-1,sizeof(f));
47   int h=0,t=1;q[1]=1;f[1]=1;
48   while (h<t)
49   {
50     int now=q[++h];if (now==n) return 1;
51     for (int i=1;i<=n;i++)
52       if (map[now][i]&&f[i]==-1)
53       {
54         f[i]=f[now]+1;
55         q[++t]=i;
56       }
57   }
58   return 0;
59 }
60 int dinic(int sta,int sum)
61 {
62   if (sta==n) return sum;int os=sum;
63   for (int i=1;(i<=n)&&os;i++)
64     if (map[sta][i]&&f[i]==f[sta]+1)
65     {
66       int Min=dinic(i,min(map[sta][i],os));
67       map[sta][i]-=Min;map[i][sta]+=Min;os-=Min;
68     }
69   if (os==sum) f[sta]=-1;return sum-os;
70 }
71 int main()
72 {
73   scanf("%d%d",&n,&m);
74   for (i=1;i<=m;i++)
75     scanf("%d%d%d%d",&x,&y,&z,&c),add(x,y,z,c),add(y,x,z,c);
76   memset(dis,60,sizeof(dis));SPFA(0,1);SPFA(1,n);
77   ans=0;init();
78   while (bfs())
79     ans+=dinic(1,INF);
80   printf("%d\n%d",dis[0][n],ans);
81   return 0;
82 }