UVa10986_Sending email(최단락)(소백서 도론 테마)

문제 풀이 보고서
생각:
벌거벗은 최단로.
#include 
#include 
#include 
#include 
#define inf 0x3f3f3f3f
#define N 40000
#define M 100000
using namespace std;
struct node
{
    int v,w,next;
}edge[M];
int head[N],dis[N],vis[N],cnt,n,m,s,t;
void add(int u,int v,int w)
{
    edge[cnt].v=v;
    edge[cnt].w=w;
    edge[cnt].next=head[u];
    head[u]=cnt++;
}
void spfa()
{
    for(int i=0;iQ;
    Q.push(s);
    while(!Q.empty()){
        int u=Q.front();
        Q.pop();
        vis[u]=0;
        for(int i=head[u];i!=-1;i=edge[i].next)
        {
            int v=edge[i].v;
            if(dis[v]>dis[u]+edge[i].w)
            {
                dis[v]=dis[u]+edge[i].w;
                if(!vis[v])
                {
                    vis[v]=1;
                    Q.push(v);
                }
            }
        }
    }
}
int main()
{
    int i,j,T,u,v,w,k=1;
    scanf("%d",&T);
    while(T--)
    {
        memset(head,-1,sizeof(head));
        cnt=0;
        scanf("%d%d%d%d",&n,&m,&s,&t);
        for(i=0;i

Problem E
Sending email
Time Limit: 3 seconds
"A new internet watchdog is creating a stir in Springfield. Mr. X, if that is his real name, has come up with a sensational scoop."
Kent Brockman
There are n SMTP servers connected by network cables. Each of the m cables connects two computers and has a certain latency measured in milliseconds required to send an email message. What is the shortest time required to send a message from server S to server T along a sequence of cables? Assume that there is no delay incurred at any of the servers.
Input The first line of input gives the number of cases, N. N test cases follow. Each one starts with a line containing n(2<=n<20000), m (0<=m<50000), S (0<=SOutput For each test case, output the line "Case #x:"followed by the number of milliseconds required to send a message from S toT. Print "unreachable"if there is no route from S to T.
Sample Input
Sample Output
3
2 1 0 1
0 1 100
3 3 2 0
0 1 100
0 2 200
1 2 50
2 0 0 1
Case #1: 100
Case #2: 150
Case #3: unreachable

Problemsetter: Igor Naverniouk

좋은 웹페이지 즐겨찾기