以下是我的代码：

#include<iostream>
#include<queue>
#include<algorithm>
#include<cstring>
#include<vector>
#include<cstdio>
using namespace std;
int n,m,k,minx,miny,minstep=1e9;
int a[3010][3010],d[3010][3010];
bool b[3010][3010],flag[3010][3010],f,ff,fff[9000010];
int dx[]={0,-1,1,0,0};
int dy[]={0,0,0,-1,1};
struct node{int x,y,step;};
bool operator<(const node &x,const node &y){
    return x.step>y.step;
}
void bfs2()
{
    priority_queue<node>q;
    q.push({1,1,0});
    flag[1][1]=1;
    while(!q.empty())
    {
        int x=q.top().x,y=q.top().y,step=q.top().step;
        q.pop();
        //cout<<x<<" "<<y<<" "<<step<<" "<<flag[x][y]<<endl;
        if(x==n&&y==m)
        {
            printf("%d\n",step);
            exit(0);
        }
        for(int i=1;i<=4;i++)
        {
            int nx=x+dx[i],ny=y+dy[i];
            if(nx<1||nx>n||ny<1||ny>m)continue;
            if(!a[nx][ny])continue;
            if(flag[nx][ny])continue;
            flag[nx][ny]=1;
            q.push({nx,ny,step+1});
        }
        if(b[x][y]&&!ff)
        {
            for(int i=1;i<=n;i++)
                for(int j=1;j<=m;j++)
                    if(b[i][j]&&!flag[i][j])
                    {
                        flag[i][j]=1;
                        if(a[x][y]==a[i][j])q.push({i,j,step+1});
                        else q.push({i,j,step+2});
                    }
            ff=1;
        }
    }
}
int main()
{
    scanf("%d%d%d",&n,&m,&k);
    for(int i=1;i<=n;i++)
        for(int j=1;j<=m;j++)
            scanf("%d",&a[i][j]);
    for(int i=1;i<=k;i++)
    {
        int x,y;
        scanf("%d%d",&x,&y);
        if(!a[x][y])continue;
        b[x][y]=1;
    }
    memset(d,999999,sizeof(d));
    //for(int i=0;i<=n*m;i++)cout<<minx[i]<<" "<<miny[i]<<endl;
    memset(flag,0,sizeof(flag));
    bfs2();
    printf("-1\n");
    return 0;
}

这份代码 AC 了，但是用这组数据能 hack

Input:
4 4 4
1 2 1 1
1 1 1 1
1 1 1 1
1 1 1 2
1 2
4 4
2 1
3 3
Output:
2