#include<stdio.h>
#include<string.h>
#define M 1000005
#define INF 0xfffffff

int n,m;
int dis1[M];
int dis2[M];
int que[M*10];
bool inq[M];
int head1[M];
int head2[M];
int tot1,tot2;

struct node
{
	int to,v,next;
}edge1[M],edge2[M];

void add1(int a,int b,int c)
{
	edge1[tot1].to=b; edge1[tot1].v=c;
	edge1[tot1].next=head1[a]; head1[a]=tot1++;
}

void add2(int a,int b,int c)
{
	edge2[tot2].to=b; edge2[tot2].v=c;
	edge2[tot2].next=head2[a]; head2[a]=tot2++;
}

void SPFA_1()
{
	int i,p;
	int r=0,l=0;
	for(i=1;i<=n;i++)
	{
		dis1[i]=INF;
		inq[i]=false;
	}
	dis1[1]=0;
	que[r++]=1;
	inq[1]=true;
	while(l<r)
	{
		p=que[l++];
		inq[p]=false;
		for(i=head1[p];i!=-1;i=edge1[i].next)
		{
			int u=edge1[i].to;
			if(dis1[u]>dis1[p]+edge1[i].v)
			{
				dis1[u]=dis1[p]+edge1[i].v;
				if(!inq[u])
				{
					inq[u]=true;
					que[r++]=u;
				}
			}
		}
	}
}

void SPFA_2()
{
	int i,p;
	int r=0,l=0;
	for(i=1;i<=n;i++)
	{
		dis2[i]=INF;
		inq[i]=false;
	}
	dis2[1]=0;
	que[r++]=1;
	inq[1]=true;
	while(l<r)
	{
		p=que[l++];
		inq[p]=false;
		for(i=head2[p];i!=-1;i=edge2[i].next)
		{
			int u=edge2[i].to;
			if(dis2[u]>dis2[p]+edge2[i].v)
			{
				dis2[u]=dis2[p]+edge2[i].v;
				if(!inq[u])
				{
					inq[u]=true;
					que[r++]=u;
				}
			}
		}
	}
}

int main()
{
	int cas,i;
	int a,b,c;
	__int64 sum;
	scanf("%d",&cas);
	while(cas--)
	{
		scanf("%d%d",&n,&m);
		for(i=1;i<=n;i++)
			head1[i]=head2[i]=-1;
		tot1=tot2=0;
		while(m--)
		{
			scanf("%d%d%d",&a,&b,&c);
			add1(a,b,c);
			add2(b,a,c);
		}	
		SPFA_1();
		sum=0;
		for(i=1;i<=n;i++)
			sum+=dis1[i];
		SPFA_2();
		for(i=1;i<=n;i++)
			sum+=dis2[i];
		printf("%I64d\n",sum);
	}
	return 0;
}

• Re:为什么一直WA啊 (2029) ylsoi 2017-08-06 13:36:32