算法提高 道路和航路 (SPFA的SLF优化)

所以我们要用SPFA的SLF优化或者LLL优化。还有读入挂。

原题：点击打开链接（codevs 2273）

代码：

#include<bits/stdc++.h>
#include<cstdio>
#include<cstring>
#include<deque>
#define MAX 150100
#define INF 1000000000

using namespace std ;
int read()
{
	int v = 0, f = 1;
	char c =getchar();
	while( c < 48 || 57 < c ){
		if(c=='-') f = -1;
		c = getchar();
	}
	while(48 <= c && c <= 57) 
		v = v*10+c-48, c = getchar();
	return v*f;
}

struct Node{
	int v , next , cap ;
}edge[MAX];

int len;
int dis[MAX/4] , head[MAX/4], c[MAX/4] ;
bool vis[MAX/4];

void addedge(int from, int to, int cap)  
{  
    edge[len].v = to;  
    edge[len].cap = cap;  
    edge[len].next = head[from];  
    head[from] = len++;  
}  
bool spfa(int s , int n)
{
	for(int i = 0 ; i <= n ; ++i)
	{
		dis[i] = INF ;
		c[i] = 0 ;
		vis[i] = false ;
	}
	dis[s] = 0 ;
	vis[s] = true ;
	deque<int> que ;
	que.push_front(s) ;
	while(!que.empty())
	{
		int k = que.front() ;
		que.pop_front() ;
		vis[k] = false ;
		c[k]++;
		if(c[k]>n) return false ;
		
		for(int i = head[k] ; i != -1 ; i = edge[i].next)
		{
			if(dis[edge[i].v] > dis[k]+edge[i].cap)
			{
				dis[edge[i].v] = dis[k]+edge[i].cap ;
				if(que.empty())
				{
					que.push_front(edge[i].v) ;
					vis[edge[i].v] = true ;
				}
				else if(!vis[edge[i].v])
				{
					if(dis[edge[i].v] > dis[que.front()])
					{
						que.push_back(edge[i].v) ;
					}
					else
					{
						que.push_front(edge[i].v) ;
					}
					vis[edge[i].v] = true ;
				}
			}
		}
	}
	return true ;
}

int main()
{	
	    int t,r,p,s;
	    int a,b,c;
	    t=read();r=read();p=read();s=read(); 
		memset(head,-1,sizeof(head)) ;
		for(int i = 0 ; i < r; i++)
		{	
		
			a=read();b=read();c=read();
			addedge(a,b,c);
			addedge(b,a,c);
		}
		for(int i = 0 ; i < p ; i++)
		{
			
			a=read();b=read();c=read();
			addedge(a,b,c);
		}
		spfa(s,t) ;
		for(int i = 1 ; i <= t ; i++)
		{
			if(dis[i] >= INF)
			{
				puts("NO PATH") ;
			}
			else
			{
				printf("%d\n",dis[i]) ;
			}
		}	
	return 0 ;
}