BZOJ1002 [FJOI2007]轮状病毒

#pragma GCC optimize(2)
#include<set>
#include<map>
#include<queue>
#include<stack>
#include<cmath>
#include<cstdio>
#include<time.h>
#include<vector>
#include<cstring>
#include<stdlib.h>
#include<iostream>
#include<algorithm>
#define LL long long
using namespace std;
const int N=2e6+10;
const int M=6e6+10;
const int mod=1e9+7;
const int inf=0x3f3f3f3f;

int n,m,E,V,fir[N],dis[N],nex[M],arr[M],len[M],book[N];
struct pnt{
	int u,dis;
	bool operator < (const pnt &other) const {
		return dis>other.dis;
	}
};
priority_queue<pnt> q;

namespace FastIO {
	template<typename tp> inline void read(tp &x) {
		x=0; char c=getchar(); bool f=0;
		for(;c<'0'||c>'9';f|=(c=='-'),c = getchar());
		for(;c>='0'&&c<='9';x=(x<<3)+(x<<1)+c-'0',c = getchar());
		if(f) x=-x;
	}
	template<typename tp> inline void write(tp x) {
	  if (x==0) return (void) (putchar('0'));
     if (x<0) putchar('-'),x=-x;
     int pr[20]; register int cnt=0;
     for (;x;x/=10) pr[++cnt]=x%10;
     while (cnt) putchar(pr[cnt--]+'0');
	}
	template<typename tp> inline void writeln(tp x) {
		write(x);
		putchar('\n');
	}
}
using namespace FastIO;

void Add_Edge(int x,int y,int l) {
	nex[++E]=fir[x];
	fir[x]=E;
	len[E]=l;
	arr[E]=y;
}

inline void Init() {
	read(n); read(m);
	V=2*(n-1)*(m-1);
	int x=1;
	if (n==1||m==1) {
		int ans=inf,l;
		while (~scanf("%d",&l)) ans=min(ans,l);
		printf("%d",ans);
		exit(0);
	}
	for (int i=1;i<=n;i++)
		for (int j=1;j<m;j++) {
			int l; read(l);
			if (i==1) Add_Edge(x,0,l),Add_Edge(0,x,l);
			else if (i==n) Add_Edge(x,V+1,l),Add_Edge(V+1,x,l);
			else Add_Edge(x,x-2*m+3,l),Add_Edge(x-2*m+3,x,l);
			if (i==n-1&&j==m-1) x=2*(n-2)*(m-1)+2;
			else x+=2;
		}
	x=2;
	for (int i=1;i<n;i++)
		for (int j=1;j<=m;j++) {
			int l; read(l);
			if (j==m) Add_Edge(x-1,0,l),Add_Edge(0,x-1,l);
			else if (j==1) Add_Edge(x,V+1,l),Add_Edge(V+1,x,l);
			else Add_Edge(x,x-3,l),Add_Edge(x-3,x,l);
			if (j!=m-1) x+=2;
		}
	x=1;
	for (int i=1;i<n;i++)
		for (int j=1;j<m;j++) {
			int l; read(l);
			Add_Edge(x,x+1,l),Add_Edge(x+1,x,l);
			x+=2;
		}
}

inline void Dijkstra() {
	memset(dis,0x3f,sizeof(dis));
	dis[0]=0; q.push((pnt){0,0});
	while (!q.empty()) {
		register int u=q.top().u; q.pop();
		if (book[u]) continue;
		book[u]=1;
		for (register int i=fir[u];i;i=nex[i])
			if (dis[u]+len[i]<dis[arr[i]]) {
				dis[arr[i]]=dis[u]+len[i];
				q.push((pnt){arr[i],dis[arr[i]]});
			}
	}
}

int main() {
	Init();
	Dijkstra();
	printf("%d",dis[V+1]);
	return 0;
}