HDU 4888 Redraw Beautiful Drawings

网络流。

$s$向每一个$r[i]$连边，容量为$r[i]$。

每一个$r[i]$向每一个$c[j]$连边，容量为$k$。

每一个$c[j]$向$t$连边容量为$c[j]$。

跑最大流，中间每一条边上的容量就是那一个格子所填的数字。

唯一性判定：如果残留网络上有环，那么不唯一。

#include<map>

#include<set>

#include<ctime>

#include<cmath>

#include<queue>

#include<string>

#include<vector>

#include<cstdio>

#include<cstring>

#include<iostream>

#include<algorithm>

#include<functional>

using namespace std;

#define ms(x,y) memset(x,y,sizeof(x))

#define rep(i,j,k) for(int i=j;i<=k;i++)

#define per(i,j,k) for(int i=j;i>=k;i--)

#define loop(i,j,k) for (int i=j;i!=-1;i=k[i])

#define inone(x) scanf("%d",&x)

#define intwo(x,y) scanf("%d%d",&x,&y)

#define inthr(x,y,z) scanf("%d%d%d",&x,&y,&z)

#define infou(x,y,z,p) scanf("%d%d%d%d",&x,&y,&z,&p)

#define lson x<<1,l,mid

#define rson x<<1|1,mid+1,r

#define mp(i,j) make_pair(i,j)

#define ft first

#define sd second

typedef long long LL;

typedef pair<int, int> pii;

const int low(int x) { return x&-x; }

const int INF = 0x7FFFFFFF;

const int mod = 1e9 + ;

const int N = 4e5 + ;

const double eps = 1e-;

int n,m,k;

const int maxn =  + ;

struct Edge

{

    int from, to, cap, flow;

    Edge(int u, int v, int c, int f) :from(u), to(v), cap(c), flow(f){}

};

vector<Edge>edges;

vector<int>G[maxn],GG[maxn];

bool vis[maxn];

int d[maxn];

int cur[maxn],q[maxn];

int s, t,FF,sz;

void init()

{

    for (int i = ; i < maxn; i++) G[i].clear();

    for (int i = ; i < maxn; i++) GG[i].clear();

    edges.clear();

}

void AddEdge(int from, int to, int cap)

{

    edges.push_back(Edge(from, to, cap, ));

    edges.push_back(Edge(to, from, , ));

    int w = edges.size();

    G[from].push_back(w - );

    G[to].push_back(w - );

}

bool BFS()

{

    memset(vis, , sizeof(vis));

    queue<int>Q;

    Q.push(s);

    d[s] = ;

    vis[s] = ;

    while (!Q.empty())

    {

        int x = Q.front();

        Q.pop();

        for (int i = ; i<G[x].size(); i++)

        {

            Edge e = edges[G[x][i]];

            if (!vis[e.to] && e.cap>e.flow)

            {

                vis[e.to] = ;

                d[e.to] = d[x] + ;

                Q.push(e.to);

            }

        }

    }

    return vis[t];

}

int DFS(int x, int a)

{

    if (x == t || a == )

        return a;

    int flow = , f;

    for (int &i = cur[x]; i<G[x].size(); i++)

    {

        Edge e = edges[G[x][i]];

        if (d[x]+ == d[e.to]&&(f=DFS(e.to,min(a,e.cap-e.flow)))>)

        {

            edges[G[x][i]].flow+=f;

            edges[G[x][i] ^ ].flow-=f;

            flow+=f;

            a-=f;

            if(a==) break;

        }

    }

    if(!flow) d[x] = -;

    return flow;

}

int dinic(int s, int t)

{

    int flow = ;

    while (BFS())

    {

        memset(cur, , sizeof(cur));

        flow += DFS(s, INF);

    }

    return flow;

}

void D(int x,int y)

{

    for(int i=;i<GG[x].size();i++)

    {

        if(GG[x][i]==y) continue;

        if(q[GG[x][i]]) { FF=; return; }

        q[GG[x][i]]=;

        D(GG[x][i],x); if(FF ) return ;

        q[GG[x][i]]=;

    }

}

int main()

{

    while(~scanf("%d%d%d",&n,&m,&k))

    {

        init();

        s=, t=n+m+;

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

        {

            int x; scanf("%d",&x);

            AddEdge(s,i,x);

        }

        for(int i=;i<=m;i++)

        {

            int x; scanf("%d",&x);

            AddEdge(n+i,t,x);

        }

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

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

                AddEdge(i,n+j,k);

        dinic(s,t);

        bool fail=;

        for(int i=;i<edges.size();i=i+)

        {

            if(edges[i].from==s && edges[i].flow<edges[i].cap) fail=;

            if(edges[i].to==t && edges[i].flow<edges[i].cap) fail=;

        }

        if(fail) printf("Impossible\n");

        else

        {

            FF=; memset(vis,,sizeof vis);

            for(int i=;i<edges.size();i=i+)

            {

                if(edges[i].flow<edges[i].cap)

                {

                    if(edges[i].from==s||edges[i].from==t) continue;

                    if(edges[i].to==s||edges[i].to==t) continue;

                    GG[edges[i].to].push_back(edges[i].from);

                }

            }

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

            {

                memset(q,,sizeof q);

                q[i]=; D(i,-);

                if(FF) break;

            }

            if(FF==)

            {

                printf("Not Unique\n");

                continue;

            }

            printf("Unique\n");

            int now=;

            for(int i=;i<edges.size();i=i+)

            {

                if(edges[i].from==s) continue;

                if(edges[i].to==t) continue;

                printf("%d",edges[i].flow);

                if(now%m==) printf("\n");

                else printf(" ");

                now++;

            }

        }

    }

    return ;

}