Fantastic Graph 2018 沈阳赛区网络预赛 F题

#include <bits/stdc++.h>
#define mem(a, b) memset(a, b, sizeof(a))
#define rap(i, a, n) for(int i=a; i<=n; i++)
#define rep(i, a, n) for(int i=a; i<n; i++)
#define lap(i, a, n) for(int i=n; i>=a; i--)
#define lep(i, a, n) for(int i=n; i>a; i--)
#define rd(a) scanf("%d", &a)
#define rlld(a) scanf("%lld", &a)
#define rc(a) scanf("%c", &a)
#define rs(a) scanf("%s", a)
#define pd(a) printf("%d\n", a);
#define plld(a) printf("%lld\n", a);
#define pc(a) printf("%c\n", a);
#define ps(a) printf("%s\n", a);
#define MOD 2018
#define LL long long
#define ULL unsigned long long
using namespace std;
const int maxn = 100100, INF = 0x7fffffff;
int d[maxn], head[maxn], in[maxn], low[maxn], id[maxn], cur[maxn];
int n, m, s, t, ans_flow, ans, cnt, k, ss, tt;
struct node{
    int u, v, c, next;
}Node[maxn<<1];

void add_(int u, int v, int c)
{
    Node[cnt].u = u;
    Node[cnt].v = v;
    Node[cnt].c = c;
    Node[cnt].next = head[u];
    head[u] = cnt++;
}

void add(int u, int v, int c)
{
    add_(u, v, c);
    add_(v, u, 0);
}

int bfs()
{
    queue<int> Q;
    mem(d, 0);
    Q.push(s);
    d[s] = 1;
    while(!Q.empty())
    {
        int u = Q.front(); Q.pop();
        for(int i=head[u]; i!=-1; i=Node[i].next)
        {
            node e = Node[i];
            if(!d[e.v] && e.c > 0)
            {
                d[e.v] = d[e.u] + 1;
                Q.push(e.v);
                if(e.v == t) return 1;
            }
        }
    }
    return d[t] != 0;
}

int dfs(int u, int cap)
{
   int ret = 0;
    if(u == t || cap == 0)
        return cap;
    for(int &i=cur[u]; i!=-1; i=Node[i].next)
    {
        node e = Node[i];
        if(d[e.v] == d[e.u] + 1 && e.c > 0)
        {
            int V = dfs(e.v, min(cap, e.c));
            if(V > 0)
            {
                Node[i].c -= V;
                Node[i^1].c += V;
                ret += V;
                cap -= V;
                if(cap == 0) break;
            }
        }
    }
    if(cap > 0) d[u] = -1;
    return ret;
}

int Dinic(int u)
{
    int sum_flow = 0;
    while(bfs())
    {
        memcpy(cur, head, sizeof(head));
        sum_flow += dfs(u, INF);

    }
    return sum_flow;
}

int main()
{
    int l, r;
    int kase = 0;
    while(~scanf("%d%d%d", &n, &m, &k))
    {
        ans_flow = 0;
        mem(head, -1);
        mem(in, 0);
        cnt = 0;
        rd(l), rd(r);
        ss = n+m+1, tt = n+m+2;
        s = 0, t = n+m+3;
        int u, v;
        for(int i=0; i<k; i++)
        {
            rd(u), rd(v);
            add(u, n+v, 1);
        }
        for(int i=1; i<=n; i++)
        {
            add(ss, i, r-l);
            add(s, i, l);
        }
        for(int i=1; i<=m; i++)
        {
            add(n+i, tt, r-l);
            add(n+i, t, l);
        }

        add(ss, t, l*n);
        add(s, tt, l*m);
        add(tt, ss, INF);
        ans_flow = l*(n+m);
        int sum_flow = Dinic(s);
        printf("Case %d: ", ++kase);
        if(sum_flow == ans_flow)
            puts("Yes");
        else
            puts("No");
    }

    return 0;
}