zoj2314(원본 송금 상하계 실행 가능한 흐름 없음)

Reactor Cooling
Time Limit: 5 Seconds      
Memory Limit: 32768 KB      
Special Judge
The terrorist group leaded by a well known international terrorist Ben Bladen is buliding a nuclear reactor to produce plutonium for the nuclear bomb they are planning to create. Being the wicked computer genius of this group, you are responsible for developing the cooling system for the reactor.
The cooling system of the reactor consists of the number of pipes that special cooling liquid flows by. Pipes are connected at special points, called nodes, each pipe has the starting node and the end point. The liquid must flow by the pipe from its start point to its end point and not in the opposite direction.
Let the nodes be numbered from 1 to N. The cooling system must be designed so that the liquid is circulating by the pipes and the amount of the liquid coming to each node (in the unit of time) is equal to the amount of liquid leaving the node. That is, if we designate the amount of liquid going by the pipe from i-th node to j-th as fij, (put fij = 0 if there is no pipe from node i to node j), for each i the following condition must hold: f
i,1+f
i,2+...+f
i,N = f
1,i+f
2,i+...+f
N,i
Each pipe has some finite capacity, therefore for each i and j connected by the pipe must be fij <= cij where cij is the capacity of the pipe. To provide sufficient cooling, the amount of the liquid flowing by the pipe going from i-th to j-th nodes must be at least lij, thus it must be fij >= lij.
Given cij and lij for all pipes, find the amount fij, satisfying the conditions specified above.
This problem contains multiple test cases!
The first line of a multiple input is an integer N, then a blank line followed by N input blocks. Each input block is in the format indicated in the problem description. There is a blank line between input blocks.
The output format consists of N output blocks. There is a blank line between output blocks.
Input
The first line of the input file contains the number N (1 <= N <= 200) - the number of nodes and and M - the number of pipes. The following M lines contain four integer number each - i, j, lij and cij each. There is at most one pipe connecting any two nodes and 0 <= lij <= cij <= 10^5 for all pipes. No pipe connects a node to itself. If there is a pipe from i-th node to j-th, there is no pipe from j-th node to i-th.
Output
On the first line of the output file print YES if there is the way to carry out reactor cooling and NO if there is none. In the first case M integers must follow, k-th number being the amount of liquid flowing by the k-th pipe. Pipes are numbered as they are given in the input file.
Sample Input
2 4 6 1 2 1 2 2 3 1 2 3 4 1 2 4 1 1 2 1 3 1 2 4 2 1 2 4 6 1 2 1 3 2 3 1 3 3 4 1 3 4 1 1 3 1 3 1 3 4 2 1 3
Sample Input
NO YES 1 2 3 2 1 1
Author: 
Andrew Stankevich
Source: Andrew Stankevich's Contest #1
제목:http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=2314
분석: 제목은 상하계를 만족시키는 실행 가능한 흐름을 요구하고 원천과 외화를 제시하지 않았다
원천과 외화를 증가시키고 모든 변은 상계-하계에 따라 상계로 하고 하계가 없다. 그리고 모든 점의 유입과 유출 통계를 작성한다. 점의 유입과 원천의 연결 용량은 유입량의 변, 유출된 연결은 상계로 하면 된다. 최대 흐름을 한 번 하면 된다. 만약에 모든 연결 원점의 변이 만류하면 유해이다. 그렇지 않으면 해가 없다. 해는 현재 변의 유량에 원래의 하계를 더한다.
오랜만에 인터넷 스트리밍을 했는데 1A라니...
코드:

#include<cstdio>
#define min(a,b) (a<b?a:b)
using namespace std;
const int mm=88888;
const int mn=222;
const int oo=1000000000;
int node,src,dest,edge;
int ver[mm],low[mm],flow[mm],next[mm];
int head[mn],work[mn],q[mn],dis[mn],in[mn];
inline void prepare(int _node,int _src,int _dest)
{
    node=_node,src=_src,dest=_dest;
    for(int i=0;i<node;++i)head[i]=-1,in[i]=0;
    edge=0;
}
inline void addedge(int u,int v,int c)
{
    ver[edge]=v,flow[edge]=c,next[edge]=head[u],head[u]=edge++;
    ver[edge]=u,flow[edge]=0,next[edge]=head[v],head[v]=edge++;
}
bool Dinic_bfs()
{
    int i,u,v,l,r=0;
    for(i=0;i<node;++i)dis[i]=-1;
    dis[q[r++]=src]=0;
    for(l=0;l<r;++l)
        for(i=head[u=q[l]];i>=0;i=next[i])
            if(flow[i]&&dis[v=ver[i]]<0)
            {
                dis[q[r++]=v]=dis[u]+1;
                if(v==dest)return 1;
            }
    return 0;
}
int Dinic_dfs(int u,int exp)
{
    if(u==dest)return exp;
    for(int &i=work[u],v,tmp;i>=0;i=next[i])
        if(flow[i]&&dis[v=ver[i]]==dis[u]+1&&(tmp=Dinic_dfs(v,min(exp,flow[i])))>0)
        {
            flow[i]-=tmp;
            flow[i^1]+=tmp;
            return tmp;
        }
    return 0;
}
void Dinic_flow()
{
    while(Dinic_bfs())
    {
        for(int i=0;i<node;++i)work[i]=head[i];
        while(Dinic_dfs(src,oo));
    }
}
bool Limit_flow()
{
    int i;
    for(i=0;i<node;++i)
    {
        if(in[i]>0)addedge(src,i,in[i]);
        if(in[i]<0)addedge(i,dest,-in[i]);
    }
    Dinic_flow();
    for(i=head[src];i>=0;i=next[i])
        if(flow[i])return 0;
    return 1;
}
int main()
{
    int i,u,v,c,n,m,t;
    scanf("%d",&t);
    while(t--)
    {
        scanf("%d%d",&n,&m);
        prepare(n+2,0,n+1);
        for(i=0;i<m;++i)
        {
            scanf("%d%d%d%d",&u,&v,&low[i],&c);
            in[u]-=low[i],in[v]+=low[i];
            addedge(u,v,c-low[i]);
        }
        if(Limit_flow())
        {
            printf("YES
");
            for(i=0;i<m;++i)printf("%d
",flow[(i<<1)^1]+low[i]);
        }
        else printf("NO
");
        puts("");
    }
    return 0;
}