BZOJ-1001 狼抓兔子

#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <fstream>
#include <iostream>
#include <queue>
#define rep(i, l, r) for(int i=l; i<=r; i++)
#define N 1009
#define MAX 2147483647
#define clr(x, c) memset(x, c, sizeof(x))
using namespace std;
int read()
{
	int x=0, f=1; char ch=getchar();
	while (ch<‘0‘ || ch>‘9‘) { if (ch==‘-‘) f=-1; ch=getchar(); }
	while (ch>=‘0‘ && ch<=‘9‘) { x=x*10+ch-‘0‘; ch=getchar(); }
	return x*f;
}
struct edge{int y, n, z;} e[N*N*20]; int fir[N*N*2], en;
struct data
{
	int x, d;
	data(int a, int b) : x(a), d(b) {}
	bool operator < (const data &k) const { return d>k.d; }
};
int n, m, g[3][N][N], l[N][N], k, d[N*N*2];

inline void Add(int x, int y, int z)
{
	en++, e[en].y=y, e[en].z=z, e[en].n=fir[x], fir[x]=en;
	en++, e[en].y=x, e[en].z=z, e[en].n=fir[y], fir[y]=en;
}

int main()
{
	n=read(); m=read();
	rep(i, 1, n) rep(j, 1, m-1) g[1][i][j]=read();
	rep(i, 1, n-1) rep(j, 1, m) g[2][i][j]=read();
	rep(i, 1, n-1) rep(j, 1, m-1) g[0][i][j]=read();
	k=0; rep(i, 1, n-1) rep(j, 1, m-1) l[i][j]=(++k)*2; k=k*2+1;
	rep(i, 2, n-1) rep(j, 1, m-1) Add(l[i-1][j]-1, l[i][j], g[1][i][j]);
	rep(i, 1, n-1) rep(j, 2, m-1) Add(l[i][j-1], l[i][j]-1, g[2][i][j]);
	rep(i, 1, n-1) rep(j, 1, m-1) Add(l[i][j]-1, l[i][j], g[0][i][j]);
	rep(i, 1, n-1) Add(0, l[i][1]-1, g[2][i][1]); 
	rep(i, 1, m-1) Add(0, l[n-1][i]-1, g[1][n][i]);
	rep(i, 1, m-1) Add(l[1][i], k, g[1][1][i]);
	rep(i, 1, n-1) Add(l[i][m-1], k, g[2][i][m]);
	rep(i, 0, k) d[i]=MAX; 
	priority_queue <data> q; q.push(data(0, 0));
	while (d[k]==MAX)
	{
		data a=q.top();
		int x=a.x, o=fir[x], y=e[o].y; q.pop(); 
		if (d[x]!=MAX) continue; else d[x]=a.d;
		while (o)
		{
			if (d[y]==MAX) q.push(data(y, d[x]+e[o].z));
			o=e[o].n, y=e[o].y;
		}
	}
	printf("%d\n", d[k]);
	return 0;
}