HDU 4780 Candy Factory(拆点费用流)
Problem Description
A new candy factory opens in pku-town. The factory import M machines to produce high quality candies. These machines are numbered from 1 to M.
There are N candies need to be produced. These candies are also numbered from 1 to N. For each candy i , it can be produced in any machine j. It also has a producing time(si,ti) , meaning that candy i must start producing at time si and will finish at ti. Otherwise if the start time is pi(si < pi < ti) then candy will still finish at ti but need additional K*(pi - si) cost. The candy can’t be produced if pi is greater than or equal to ti. Of course one machine can only produce at most one candy at a time and can’t stop once start producing.
On the other hand, at time 0 all the machines are in their initial state and need to be “set up” or changed before starting producing. To set up Machine j from its initial state to the state which is suitable for producing candiy i, the time required is Cij and cost is Dij. To change a machine from the state suitable for candy i1 into the state suitable for candy i2, time required is Ei1i2 and cost is Fi1i2.
As the manager of the factory you have to make a plan to produce all the N candies. While the sum of producing cost should be minimized.
There are N candies need to be produced. These candies are also numbered from 1 to N. For each candy i , it can be produced in any machine j. It also has a producing time(si,ti) , meaning that candy i must start producing at time si and will finish at ti. Otherwise if the start time is pi(si < pi < ti) then candy will still finish at ti but need additional K*(pi - si) cost. The candy can’t be produced if pi is greater than or equal to ti. Of course one machine can only produce at most one candy at a time and can’t stop once start producing.
On the other hand, at time 0 all the machines are in their initial state and need to be “set up” or changed before starting producing. To set up Machine j from its initial state to the state which is suitable for producing candiy i, the time required is Cij and cost is Dij. To change a machine from the state suitable for candy i1 into the state suitable for candy i2, time required is Ei1i2 and cost is Fi1i2.
As the manager of the factory you have to make a plan to produce all the N candies. While the sum of producing cost should be minimized.
Input
There are multiple test cases.
For each case, the first line contains three integers N(1<=N<=100), M(1<=M<=100), K(1<=K<=100) . The meaning is described above.
Then N lines follow, each line contains 2 integers si and ti(0 <= si < ti <100000).
Then N lines follow, each line contains M integers, the j-th integer of the i-th line indicating Cij(1<=Cij<=100000) .
Then N lines follow, each line contains M integers, the j-th integer of the i-th line indicating Dij(1<=Dij<=100000) .
Then N lines follow, each line contains N integers, the i2-th integer of the i1-th line indicating Ei1i2(1<=Ei1j2<=100000) .
Then N lines follow, each line contains N integers, the i2-th integer of the i1-th line indicating Fi1i2(1 <= Fi1j2<=100000) .
Since the same candy will only be produced once, Eii and Fii are meaningless and will always be -1.
The input ends by N=0 M=0 K=0. Cases are separated with a blank line.
For each case, the first line contains three integers N(1<=N<=100), M(1<=M<=100), K(1<=K<=100) . The meaning is described above.
Then N lines follow, each line contains 2 integers si and ti(0 <= si < ti <100000).
Then N lines follow, each line contains M integers, the j-th integer of the i-th line indicating Cij(1<=Cij<=100000) .
Then N lines follow, each line contains M integers, the j-th integer of the i-th line indicating Dij(1<=Dij<=100000) .
Then N lines follow, each line contains N integers, the i2-th integer of the i1-th line indicating Ei1i2(1<=Ei1j2<=100000) .
Then N lines follow, each line contains N integers, the i2-th integer of the i1-th line indicating Fi1i2(1 <= Fi1j2<=100000) .
Since the same candy will only be produced once, Eii and Fii are meaningless and will always be -1.
The input ends by N=0 M=0 K=0. Cases are separated with a blank line.
Output
For each test case, if all of M candies can be produced, output the sum of minimum producing cost in a single line. Otherwise output -1.
Sample Input
3 2 1
4 7
2 4
8 9
4 4
3 3
3 3
2 8
12 3
14 6
-1 1 1
1 -1 1
1 1 -1
-1 5 5
5 -1 5
5 5 -1
1 1 2
1 5
5
5
-1
-1
0 0 0
Sample Output
11
-1
![](http://acm.hdu.edu.cn/data/images/C486-1011-1.jpg)
In the picture, S i represents setting up time for candy i, A i represents changing time for candy i and P i represents producing time for candy i .
So the total cost includes:
Hint
For the first example, the answer can be achieved in the following way:![](http://acm.hdu.edu.cn/data/images/C486-1011-1.jpg)
setting up machine 1 for candy 1, costs 2
setting up machine 2 for candy 2, costs 3
changing state from candy 2 to candy 3, costs 5
late start of candy 2, costs 1
题意
有N个糖果需要被生产,有M个机器,K代表额外花费系数
N行代表第i个糖果只能在[s[i],t[i]]的时间内被生产
接下来N*M代表生产第i个糖果的机器j在C[i][j]时间被开启
接下来N*M代表生产糖果i机器j的基础花费D[i][j],如果在第s[i]<p<t[i]的时间开始生产,也可以在t[i]生产出糖果,但需要额外花费(p-s[i])*K的花费
接下来N*N代表把机器J正在生产i糖果改成生产j糖果,所需的额外时间为E[i][j]
接下来N*N代表把机器J正在生产i糖果改成生产j糖果,所需的基础花费F[i][j],如果在第s[j]<p<t[j]的时间开始生产,也可以在t[j]生产出糖果,但需要额外花费(p-s[j])*K的花费
题解
一道比较复杂的费用流题,题意读了很久
为了保证糖果从源点S流出一次从汇点T流入一次,可以把N个糖果拆成左右糖,然后(S,左糖,1,0),然后(右糖,T,1,0)
然后考虑一个机器生产完i再去生产j的情况,如果时间允许,就连(左糖i,右糖j,1,基础花费F+额外花费)
然后新建一个点u,(S,u,m,0),(u,每个机器,1,0),如果机器i生产糖果j的时间C[j][i]<t[j]就连线(机器,右糖,1,基础花费D+额外花费)
代码
1 #include<bits/stdc++.h> 2 using namespace std; 3 4 const int N=1e5+5; 5 const int M=2e5+5; 6 const int INF=0x3f3f3f3f; 7 8 int FIR[N],FROM[M],TO[M],CAP[M],FLOW[M],COST[M],NEXT[M],tote; 9 int pre[N],dist[N],q[400000]; 10 bool vis[N]; 11 int n,m,S,T; 12 void init() 13 { 14 tote=0; 15 memset(FIR,-1,sizeof(FIR)); 16 } 17 void addEdge(int u,int v,int cap,int cost) 18 { 19 FROM[tote]=u; 20 TO[tote]=v; 21 CAP[tote]=cap; 22 FLOW[tote]=0; 23 COST[tote]=cost; 24 NEXT[tote]=FIR[u]; 25 FIR[u]=tote++; 26 27 FROM[tote]=v; 28 TO[tote]=u; 29 CAP[tote]=0; 30 FLOW[tote]=0; 31 COST[tote]=-cost; 32 NEXT[tote]=FIR[v]; 33 FIR[v]=tote++; 34 } 35 bool SPFA(int s, int t) 36 { 37 memset(dist,INF,sizeof(dist)); 38 memset(vis,false,sizeof(vis)); 39 memset(pre,-1,sizeof(pre)); 40 dist[s] = 0;vis[s]=true;q[1]=s; 41 int head=0,tail=1; 42 while(head!=tail) 43 { 44 int u=q[++head];vis[u]=false; 45 for(int v=FIR[u];v!=-1;v=NEXT[v]) 46 { 47 if(dist[TO[v]]>dist[u]+COST[v]&&CAP[v]>FLOW[v]) 48 { 49 dist[TO[v]]=dist[u]+COST[v]; 50 pre[TO[v]]=v; 51 if(!vis[TO[v]]) 52 { 53 vis[TO[v]] = true; 54 q[++tail]=TO[v]; 55 } 56 } 57 } 58 } 59 return pre[t]!=-1; 60 } 61 void MCMF(int s, int t, int &cost, int &flow) 62 { 63 flow=0; 64 cost=0; 65 while(SPFA(s,t)) 66 { 67 int Min=INF; 68 for(int v=pre[t];v!=-1;v=pre[TO[v^1]]) 69 Min=min(Min,CAP[v]-FLOW[v]); 70 for(int v=pre[t];v!=-1;v=pre[TO[v^1]]) 71 { 72 FLOW[v]+=Min; 73 FLOW[v^1]-=Min; 74 cost+=COST[v]*Min; 75 } 76 flow+=Min; 77 } 78 } 79 int main() 80 { 81 int N,M,K,u,ss[105],tt[105],C[105][105],D[105][105],E[105][105],F[105][105]; 82 while(scanf("%d%d%d",&N,&M,&K)!=EOF,N||M||K) 83 { 84 init(); 85 for(int i=1;i<=N;i++) 86 scanf("%d%d",&ss[i],&tt[i]); 87 for(int i=1;i<=N;i++)for(int j=1;j<=M;j++) 88 scanf("%d",&C[i][j]); 89 for(int i=1;i<=N;i++)for(int j=1;j<=M;j++) 90 scanf("%d",&D[i][j]); 91 for(int i=1;i<=N;i++)for(int j=1;j<=N;j++) 92 scanf("%d",&E[i][j]); 93 for(int i=1;i<=N;i++)for(int j=1;j<=N;j++) 94 scanf("%d",&F[i][j]); 95 96 S=0,u=N+N+M+1,T=N+N+1+M+1,n=T; 97 for(int i=1;i<=N;i++) 98 { 99 addEdge(S,i,1,0); 100 addEdge(N+i,T,1,0); 101 for(int j=1;j<=N;j++) 102 { 103 if(i!=j&&tt[i]+E[i][j]<tt[j]) 104 { 105 int c=(max(tt[i]+E[i][j],ss[j])-ss[j])*K; 106 addEdge(i,N+j,1,c+F[i][j]); 107 } 108 } 109 } 110 addEdge(S,u,M,0); 111 for(int i=1;i<=M;i++) 112 { 113 addEdge(u,N+N+i,1,0); 114 for(int j=1;j<=N;j++) 115 { 116 if(C[j][i]<tt[j]) 117 { 118 int c=(max(C[j][i],ss[j])-ss[j])*K; 119 addEdge(N+N+i,N+j,1,c+D[j][i]); 120 } 121 } 122 } 123 int flow,cost; 124 MCMF(S,T,cost,flow); 125 if(flow!=N)printf("-1\n"); 126 else printf("%d\n",cost); 127 } 128 return 0; 129 }