[BZOJ 1698] 荷叶池塘

[题目链接]

https://www.lydsy.com/JudgeOnline/problem.php?id=1698

[算法]

最短路

[代码]

#include<bits/stdc++.h>
using namespace std;
#define MAXN 35
const int dx[] = {,-,,-,,-,,-};
const int dy[] = {,,-,-,,,-,-};

struct edge
{
    int to,nxt;
} e[MAXN * MAXN * MAXN * MAXN];

int n,m,sx,sy,tx,ty,tot;
int head[MAXN * MAXN];
int mp[MAXN][MAXN],dist[MAXN * MAXN];
long long cnt[MAXN * MAXN];
bool visited[MAXN][MAXN];

inline bool valid(int x,int y)
{
    return x >=  && x <= n && y >=  && y <= m;
}
inline int id(int x,int y)
{
    return (x - ) * m + y;
}
inline void addedge(int u,int v)
{
    tot++;
    e[tot] = (edge){v,head[u]};
    head[u] = tot;
}
inline void dfs(int nowx,int nowy,int x,int y)
{
    for (int i = ; i < ; i++)
    {
        int nx = nowx + dx[i] , ny = nowy + dy[i];
        if (valid(nx,ny) && !visited[nx][ny] && mp[nx][ny] != )
        {
            visited[nx][ny] = true;
            if (!mp[nx][ny] || mp[nx][ny] == ) addedge(id(x,y),id(nx,ny));
            else dfs(nx,ny,x,y);
        }
    }
}
inline void spfa(int x,int y)
{
    queue< int > q;
    static bool inq[MAXN * MAXN];
    memset(inq,false,sizeof(inq));
    memset(dist,0x3f,sizeof(dist));
    dist[id(x,y)] = ;
    cnt[id(x,y)] = ;
    q.push(id(x,y));
    while (!q.empty())
    {
        int cur = q.front();
        q.pop();
        if (cur == id(tx,ty)) continue;
        inq[cur] = false;
        for (int i = head[cur]; i; i = e[i].nxt)
        {
            int v = e[i].to;
            if (dist[cur] +  < dist[v])
            {
                dist[v] = dist[cur] + ;
                cnt[v] = cnt[cur];
                if (!inq[v])
                {
                    inq[v] = true;
                    q.push(v);
                }
            } else if (dist[cur] +  == dist[v]) cnt[v] += cnt[cur];
        }
        cnt[cur] = ;
    }
}

int main()
{

    scanf("%d%d",&n,&m);
    for (int i = ; i <= n; i++)
    {
        for (int j = ; j <= m; j++)
        {
            scanf("%d",&mp[i][j]);
            if (mp[i][j] == )
            {
                sx = i;
                sy = j;
            }
            if (mp[i][j] == )
            {
                tx = i;
                ty = j;
            }
        }
    }
    for (int i = ; i <= n; i++)
    {
        for (int j = ; j <= m; j++)
        {
            memset(visited,false,sizeof(visited));
            visited[i][j] = true;
            if (mp[i][j] != )
                dfs(i,j,i,j);
        }
    }
    spfa(sx,sy);
    if (dist[id(tx,ty)] > 1e8)
    {
        printf("-1\n");
        return ;
    }
    printf("%d\n%lld\n",dist[id(tx,ty)] - ,cnt[id(tx,ty)]);

    return ;
}