Leapin' Lizards [HDU - 2732]【网络流最大流】

题目链接

网络流直接最大流就是了，只是要拆点小心一个点的流超出了原本的正常范围才是。

#include <iostream>
#include <cstdio>
#include <cmath>
#include <string>
#include <cstring>
#include <algorithm>
#include <limits>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#define lowbit(x) ( x&(-x) )
#define pi 3.141592653589793
#define e 2.718281828459045
#define INF 0x3f3f3f3f
#define HalF (l + r)>>1
#define lsn rt<<1
#define rsn rt<<1|1
#define Lson lsn, l, mid
#define Rson rsn, mid+1, r
#define QL Lson, ql, qr
#define QR Rson, ql, qr
#define myself rt, l, r
using namespace std;
typedef unsigned long long ull;
typedef long long ll;
const int maxN = , maxE = 3e4 + , st = ;
int N, D, M, all, head[], cur[], cnt, ed;
char liz[maxN][maxN], jump[maxN][maxN];
struct Eddge
{
    int nex, to, flow;
    Eddge(int a=-, int b=, int c=):nex(a), to(b), flow(c) {}
}edge[maxE];
inline void addEddge(int u, int v, int w)
{
    edge[cnt] = Eddge(head[u], v, w);
    head[u] = cnt++;
}
inline void _add(int u, int v, int w) { addEddge(u, v, w); addEddge(v, u, ); }
inline int _id(int x, int y) { return (x - ) * M + y; }
inline bool can_out(int x, int y) { return x <= D || y <= D || (N - x < D) || (M - y < D); }
bool In_map(int x, int y) { return x >=  && y >=  && x <= N && y<= M; }
int deep[];
queue<int> Q;
inline bool bfs()
{
    for(int i=; i<=ed; i++) deep[i] = ;
    while(!Q.empty()) Q.pop();
    Q.push(st); deep[st] = ;
    while(!Q.empty())
    {
        int u = Q.front(); Q.pop();
        for(int i=head[u], v, f; ~i; i=edge[i].nex)
        {
            v = edge[i].to; f = edge[i].flow;
            if(f && !deep[v])
            {
                deep[v] = deep[u] + ;
                Q.push(v);
            }
        }
    }
    return deep[ed];
}
inline int dfs(int u, int dist)
{
    if(u == ed) return dist;
    for(int &i=cur[u], v, f; ~i; i=edge[i].nex)
    {
        v = edge[i].to; f = edge[i].flow;
        if(f && deep[v] == deep[u] + )
        {
            int di = dfs(v, min(dist, f));
            if(di)
            {
                edge[i].flow -= di;
                edge[i^].flow += di;
                return di;
            }
        }
    }
    return ;
}
inline int Dinic()
{
    int ans = , tmp;
    while(bfs())
    {
        for(int i=; i<=ed; i++) cur[i] = head[i];
        while((tmp = dfs(st, INF))) ans += tmp;
    }
    return ans;
}
inline void init()
{
    all =cnt = ;
    memset(head, -, sizeof(head));
}
int main()
{
    int T; scanf("%d", &T);
    for(int Cas=; Cas<=T; Cas++)
    {
        scanf("%d%d", &N, &D);
        init();
        for(int i=; i<=N; i++) scanf("%s", jump[i] + );
        M = (int)strlen(jump[] + );
        ed =  * N * M + ;
        for(int i=; i<=N; i++)
        {
            scanf("%s", liz[i] + );
            for(int j=; j<=M; j++)
            {
                if(liz[i][j] == 'L')
                {
                    all++;
                    _add(st, _id(i, j), );
                }
            }
        }
        for(int i=, u, v; i<=N; i++)
        {
            for(int j=; j<=M; j++)
            {
                u = _id(i, j);
                if(jump[i][j] > '')
                {
                    _add(u, u + N * M, jump[i][j] - '');
                    if(can_out(i, j))
                    {
                        _add(u + N * M, ed, jump[i][j] - '');
                        continue;
                    }
                    for(int x=; x<=D; x++)
                    {
                        for(int y=D-x; y>=; y--)
                        {
                            if(!x && !y) continue;
                            if(In_map(i + x, j + y))
                            {
                                v = _id(i + x, j + y);
                                _add(u + N * M, v, jump[i][j] - '');
                            }
                            if(In_map(i - x, j + y))
                            {
                                v = _id(i - x, j + y);
                                _add(u + N * M, v, jump[i][j] - '');
                            }
                            if(In_map(i + x, j - y))
                            {
                                v = _id(i + x, j - y);
                                _add(u + N * M, v, jump[i][j] - '');
                            }
                            if(In_map(i - x, j - y))
                            {
                                v = _id(i - x, j - y);
                                _add(u + N * M, v, jump[i][j] - '');
                            }
                        }
                    }
                }
            }
        }
        printf("Case #%d: ", Cas);
        int ans = all - Dinic();
        if(ans == ) printf("no lizard was left behind.\n");
        else if(ans == ) printf("1 lizard was left behind.\n");
        else printf("%d lizards were left behind.\n", ans);
    }
    return ;
}