[poj 3436]最大流+输出结果每条边流量

题目链接:http://poj.org/problem?id=3436

大力套kuangbin板过了orz

#include<cstdio>
#include<cstring>
using namespace std;

const int MAXN = 210;
const int MAXM = 40010;
const int INF = 0x3f3f3f3f;
struct Edge
{
    int to,next,cap,flow;
} edge[MAXM];
int tol;
int head[MAXN];
int gap[MAXN],dep[MAXN],pre[MAXN],cur[MAXN];
void init()
{
    tol = 0;
    memset(head,-1,sizeof(head));
}
void addedge(int u,int v,int w,int rw=0)
{
    edge[tol].to = v;
    edge[tol].cap = w;
    edge[tol].next = head[u];
    edge[tol].flow = 0;
    head[u] = tol++;
    edge[tol].to = u;
    edge[tol].cap = rw;
    edge[tol].next = head[v];
    edge[tol].flow = 0;
    head[v]=tol++;
}
int sap(int start,int end,int N)
{
    memset(gap,0,sizeof(gap));
    memset(dep,0,sizeof(dep));
    memcpy(cur,head,sizeof(head));
    int u = start;
    pre[u] = -1;
    gap[0] = N;
    int ans = 0;
    while(dep[start] < N)
    {
        if(u == end)
        {
            int Min = INF;
            for(int i = pre[u]; i != -1; i = pre[edge[i^1].to])
                if(Min > edge[i].cap - edge[i].flow)
                    Min = edge[i].cap - edge[i].flow;
            for(int i = pre[u]; i != -1; i = pre[edge[i^1].to])
            {
                edge[i].flow += Min;
                edge[i^1].flow -= Min;
            }
            u = start;
            ans += Min;
            continue;
        }
        bool flag = false;
        int v;
        for(int i = cur[u]; i != -1; i = edge[i].next)
        {
            v = edge[i].to;
            if(edge[i].cap - edge[i].flow && dep[v]+1 == dep[u])
            {
                flag = true;
                cur[u] = pre[v] = i;
                break;
            }
        }
        if(flag)
        {
            u = v;
            continue;
        }
        int Min = N;
        for(int i = head[u]; i != -1; i = edge[i].next)
            if(edge[i].cap - edge[i].flow && dep[edge[i].to] < Min)
            {
                Min = dep[edge[i].to];
                cur[u] = i;
            }
        gap[dep[u]]--;
        if(!gap[dep[u]])return ans;
        dep[u] = Min+1;
        gap[dep[u]]++;
        if(u != start) u = edge[pre[u]^1].to;
    }
    return ans;
}

int P;

bool jr(int out,int in)
{
    for (int i=0; i<P; i++)
    {
        int tout=out%3;
        int tin=in%3;
        if (tout==0 && tin==1 || tout==1 && tin==0) return false;
        out/=3;
        in/=3;
    }
    return true;
}

int input[MAXN],output[MAXN];
int ef[MAXN];

int main()
{
    init();
    int n;
    scanf("%d%d",&P,&n);
    for (int i=0; i<n; i++)
    {
        scanf("%d",&ef[i]);
        int tout=0,tin=0;
        for (int j=0; j<P; j++)
        {
            int x;
            scanf("%d",&x);
            tin=tin*3+x;
        }
        for (int j=0; j<P; j++)
        {
            int x;
            scanf("%d",&x);
            tout=tout*3+x;
        }
        input[i]=tin;
        output[i]=tout;
    }
    output[n]=0;
    input[n+1]=0;
    for (int j=0; j<P; j++) input[n+1]=input[n+1]*3+1;
    for (int i=0;i<n;i++) addedge(i,i+n,ef[i]);
    for (int i=0; i<n; i++)
        for (int j=0; j<n; j++)
        {
            if (jr(output[i],input[j]))
            {
                addedge(i+n,j,ef[i]);
            }
        }
    for (int i=0; i<n; i++) if (jr(output[n],input[i])) addedge(n+n,i,INF);
    for (int i=0; i<n; i++) if (jr(output[i],input[n+1])) addedge(i+n,n+n+1,ef[i]);

    printf("%d ",sap(n+n,n+n+1,n+n+2));

    int cnt=0;
    for (int i=0;i<n;i++)
    {
        for (int j=head[i+n];j!=-1;j=edge[j].next)
        {
            if (edge[j].flow>0 && edge[j].to>=0 && edge[j].to<n) cnt++;
        }
    }
    printf("%d
",cnt);
    for (int i=0;i<n;i++)
    {
        for (int j=head[i+n];j!=-1;j=edge[j].next)
        {
            if (edge[j].flow>0 && edge[j].to>=0 && edge[j].to<n) printf("%d %d %d
",i+1,edge[j].to+1,edge[j].flow);
        }
    }
    return 0;
}
原文地址:https://www.cnblogs.com/acmsong/p/7460917.html