UVA 10735 混合图的欧拉回路判断以及输出路径

题意和POJ1635一样，只是多了一项输出路径。

#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <string>
#include <cstring>
#include <cmath>
#include <vector>
#include <queue>
#include <algorithm>
#include <map>
using namespace std;
const int maxn = 220;
const int maxm = maxn*maxn;
const int INF = 0x3f3f3f3f;
struct Edge
{
    int from, to, cap, flow;
    Edge(int from, int to, int cap, int flow): from(from), to(to), cap(cap), flow(flow) {}
};
struct Dinic
{
    int n, m, s, t;
    vector<Edge> edges;
    vector<int> G[maxn];
    bool vis[maxn];
    int d[maxn];
    int cur[maxn];
    void init(int n)
    {
        this->n = n;
        for(int i = 0; i <= n; i++) G[i].clear();
        edges.clear();
    }
    void ClearFlow ()
    {
        for(int i = 0; i < edges.size(); i++) edges[i].flow = 0;
    }
    void AddEdge(int from, int to, int cap)
    {
        edges.push_back(Edge (from, to, cap, 0));
        edges.push_back(Edge (to, from, 0, 0));
        m = edges.size();
        G[from].push_back(m-2);
        G[to].push_back(m-1);
    }
    bool BFS()
    {
        memset(vis, 0, sizeof(vis));
        queue<int> Q;
        Q.push(s);
        d[s] = 0;
        vis[s] = 1;
        while(!Q.empty())
        {
            int x = Q.front();
            Q.pop();
            for(int i = 0; i < G[x].size(); i++)
            {
                Edge& e = edges[G[x][i]];
                if(!vis[e.to] && e.cap > e.flow)
                {
                    vis[e.to] = 1;
                    d[e.to] = d[x]+1;
                    Q.push(e.to);
                }
            }
        }
        return vis[t];
    }
    int DFS(int x, int a)
    {
        if(x == t || a == 0) return a;
        int flow = 0, f;
        for(int &i = cur[x]; i < G[x].size(); i++)
        {
            Edge& e = edges[G[x][i]];
            if(d[x] + 1 == d[e.to] && (f = DFS(e.to, min(a, e.cap-e.flow))) > 0)
            {
                e.flow += f;
                edges[G[x][i]^1].flow -= f;
                flow += f;
                a -= f;
                if(a == 0) break;
            }
        }
        return flow;
    }
    int Maxflow(int s, int t)
    {
        this->s = s;
        this->t = t;
        int flow = 0;
        while(BFS())
        {
            memset(cur, 0, sizeof(cur));
            flow += DFS(s, INF);
        }
        return flow;
    }
};
int fa[maxn];
int find(int x)
{
    return x == fa[x]? x : fa[x] = find(fa[x]);
}
void Union(int x, int y)
{
    x = find(x), y = find(y);
    if(x != y) fa[x] = y;
}
Dinic dinic;
int n, m, s, t;
int ind[maxn], outd[maxn];
bool vis[maxn];
struct Edge2
{
    int v;
    bool vis;
    int next;
} edge[maxm];
int cnt;
int first[maxn];
void addedge(int u, int v)
{
    edge[cnt].v = v, edge[cnt].vis = 0;
    edge[cnt].next = first[u], first[u] = cnt++;
}
void init()
{
    cnt = 0;
    memset(first, -1, sizeof(first));
    memset(ind, 0, sizeof(ind));
    memset(outd, 0, sizeof(outd));
    memset(vis, 0, sizeof(vis));
    for(int i = 0; i <= n+2; i++) fa[i] = i;
}
void read_case()
{
    scanf("%d%d",&n,&m);
    init();
    dinic.init(n+5);
    while(m--)
    {
        int x, y;
        char c;
        scanf("%d %d %c", &x, &y, &c);
        if(c == 'D')
            addedge(x, y);
        else if(c == 'U')
            dinic.AddEdge(x, y, 1);
        vis[x] = vis[y] = 1;
        outd[x]++, ind[y]++;
        Union(x, y);
    }
}
int totflow;
int build()
{
    s = 0, t = n+1;
    totflow = 0;
    for(int i = 1; i <= n; i++)
        if(vis[i])
        {
            if((outd[i]+ind[i]) & 1)
                return 0;
            else if(outd[i] > ind[i])
            {
                int d = outd[i]-ind[i];
                dinic.AddEdge(s, i, d/2);
                totflow += d/2;
            }
            else if(ind[i] > outd[i])
            {
                int d = ind[i]-outd[i];
                dinic.AddEdge(i, t, d/2);
            }
        }
    return 1;
}
int check()
{
    int count = 0;
    for(int i = 1; i <= n; i++) if(vis[i] && fa[i] == i) count++;
    if(count > 1) return 0;

    int ans = dinic.Maxflow(s, t);
    if(ans >= totflow) return 1;
    return 0;
}
void rebuild()
{
    for(int i = 0; i < dinic.edges.size(); i++)
    {
        Edge &e = dinic.edges[i];
        if(e.cap > 0 && e.from >= 1 && e.from <= n)
        {
            if(e.flow == 0) addedge(e.from, e.to);
            else addedge(e.to, e.from);
        }
    }
}
vector<int> ans;
int Euler(int u) //套圈算法
{
    for(int e = first[u]; e != -1; e = edge[e].next)
    {
        if(edge[e].vis) continue;
        edge[e].vis = 1;
        Euler(edge[e].v);
        ans.push_back(edge[e].v);
    }
}
void output()
{
    ans.clear();
    Euler(1);
    printf("1");
    for(int i = ans.size()-1; i >= 0; i--)
        printf(" %d", ans[i]);
    printf("\n");
}
void solve()
{
    read_case();
    if(build())
    {
        if(!check()) printf("No euler circuit exist\n");
        else
        {
            rebuild();
            output();
        }
    }
    else printf("No euler circuit exist\n");
}
int main()
{
    int T;
    scanf("%d",&T);
    for(int i=0;i<T;i++)
    {
        if(i)
            printf("\n");
        solve();
    }
    return 0;
}