POJ2289-Jamie's Contact Groups-二分图多重匹配-ISAP

注意POJ数组越界可能返回TLE！！！

网络流的maxn大小要注意

其他没什么了 裸二分答案+isap乱搞

不过复杂度没搞懂 V=1e3 E = 1e5 那ISAP的O(V^2E)怎么算都不行啊

/*--------------------------------------------------------------------------------------*/

#include <algorithm>
#include <iostream>
#include <cstring>
#include <ctype.h>
#include <cstdlib>
#include <cstdio>
#include <vector>
#include <string>
#include <queue>
#include <stack>
#include <cmath>
#include <set>
#include <map>

//debug function for a N*M array
#define debug_map(N,M,G) printf("
");for(int i=0;i<(N);i++)
{for(int j=0;j<(M);j++){
printf("%d",G[i][j]);}printf("
");}
//debug function for int,float,double,etc.
#define debug_var(X) cout<<#X"="<<X<<endl;
#define LL long long
const int INF = 0x3f3f3f3f;
const LL LLINF = 0x3f3f3f3f3f3f3f3f;
/*--------------------------------------------------------------------------------------*/
using namespace std;

int N,M,T;
const int maxn = 2010;
const int maxm = 2000010;
//map<int ,string > mp;
vector <int> save[maxn];

struct Edge{
    int to,next,cap,flow;
}edge[maxm];

int head[maxn],tot;
int uN = 0;
int gap[maxn],dep[maxn],pre[maxn],cur[maxn];

void init()
{
    tot = 0;
    memset(head,-1,sizeof head);
}

void add_edge(int u,int v,int w,int rw = 0)
{
    //printf("%d->%d %d
",u,v,w);
    edge[tot].to = v;edge[tot].cap = w;edge[tot].next = head[u];
    edge[tot].flow = 0;head[u] = tot++;
    edge[tot].to = u;edge[tot].cap = rw;edge[tot].next = head[v];
    edge[tot].flow = 0;head[v] = tot++;
}
int Q[maxn];
void BFS(int st,int ed)
{
    memset(dep,-1,sizeof dep);
    memset(gap,0,sizeof gap);
    gap[0] = 1;
    int front = 0,rear = 0;
    dep[ed] = 0;
    Q[rear++] = ed;
    while(front != rear)
    {
        int u = Q[front++];
        for(int i=head[u];~i;i=edge[i].next)
        {
            int v = edge[i].to;
            if(dep[v] != -1) continue;
            Q[rear++] = v;
            dep[v] = dep[u] + 1;
            gap[dep[v]] ++;
        }
    }
}
int S[maxn];

int sap(int st,int ed)
{
    BFS(st,ed);
    memcpy(cur,head,sizeof head);
    int top = 0;
    int u = st;

    int ans = 0;
    while(dep[st] < uN)
    {
        if(u == ed)
        {
            int Min = INF;
            int inser;
            for(int i=0;i<top;i++)
            {
                if(Min > edge[S[i]].cap - edge[S[i] ].flow)
                {
                    Min = edge[S[i]].cap - edge[S[i]].flow;
                    inser=i;
                }
            }
            for(int i=0;i<top;i++)
            {
                edge[S[i]].flow += Min;
                edge[S[i]^1].flow -= Min;
            }
            ans += Min;
            top = inser;
            u = edge[S[top]^1].to;
            continue;
        }
        bool flag = false;
        int v;
        for(int i=cur[u];~i;i=edge[i].next)
        {
            v = edge[i].to;
            if(edge[i].cap - edge[i].flow && dep[v]+1 == dep[u])
            {
                flag = true;
                cur[u] = i;
                break;
            }
        }
        if(flag)
        {
            S[top++] = cur[u];
            u = v;
            continue;
        }
        int Min = uN;
        for(int i=head[u];~i;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 != st) u = edge[S[--top]^1].to;
    }
    return ans;
}

int check(int mid)
{
    uN = N+M+2;
    init();
    for(int i=0;i<N;i++)
    {
        add_edge(N+M,i,1);
        for(int j=0;j<save[i].size();j++)
        {
            add_edge(i,save[i][j]+N,1);
        }
    }
    for(int i=0;i<M;i++)
    {
        add_edge(N+i,N+M+1,mid);
    }

    int res = sap(N+M,N+M+1);
    //printf("mid:%d res:%d
",mid,res);
    if(res == N) return true;
    else return false;
}

int solve()
{
    int L = 0,R = 2*N,mid;
    while(L <= R)
    {
        mid = (L+R)>>1;
        if(check(mid))  R = mid-1;
        else L = mid+1;
    }
    //printf("%d %d
",L,R);
    return L;
}

int main()
{
    while(scanf("%d%d",&N,&M) && N+M)
    {
        char s[20];
        //mp.clear();
        for(int i=0;i<maxn;i++) save[i].clear();
        for(int i=0;i<N;i++)
        {
            scanf("%s",s);
            char c = getchar();
            if(c != ' ') continue;
            int num = -1;
            while((c = getchar()) && c !='
')
            {
                if(isdigit(c))
                {
                    if(num == -1) num = 0;
                    num *= 10;num += c-'0';
                }
                else if(c == ' ')
                {
                    save[i].push_back(num);
                    num = -1;
                }
            }
            if(num != -1) save[i].push_back(num);
        }
        if(M == 0 || N == 0) printf("0
");
        else printf("%d
",solve());
    }
}