poj 2378 (dijkstra)

时间:2023-03-09 17:54:02
poj 2378 (dijkstra)

http://poj.org/problem?id=2387

一个dijkstra的模板题

#include <stdio.h>
#include <string.h>
#define inf 999999; int graph[ ][ ];
bool mark[ ];
int m,n; void dijkstra()
{
int d[ ],k,Min;
bool mark[ ];
for(int i = ; i <= n ; i++) //对d[i]进行初始化
{
mark[ i ] = false;
d[ i ] = graph[ ][ i ];
}
for(int i = ; i <= n ; i++)
{
Min=inf;
for(int j = ; j <= n ; j++)
{
if(!mark[ j ] && d[ j ] < Min)
{
k = j;
Min = d[ j ];
}
}
mark[ k ] = true; for(int j = ; j <= n ; j++)
{
if(!mark[ j ] && d[ j ] > graph[ k ][ j ] + d[ k ])
d[ j ] = graph[ k ] [ j ] + d[ k ];
}
}
printf("%d\n",d[n]);
} int main()
{
int a,b,c;
while(~scanf("%d%d",&m,&n)){
for(int i = ; i <= n ; i++)
for(int j = ; j <= n ; j++)
if(i == j)
graph[ i ][ j ] = ;
else
{
graph[ i ][ j ] = inf;
graph[ j ][ i ] = inf;
}
for(int i = ; i <= m ;i++)
{
scanf("%d%d%d",&a,&b,&c);
if(graph[ a ][ b ] > c)
{
graph[ a ][ b ] = c;
graph[ b ][ a ] = c;
}
}
dijkstra();
}
return ;
}

dijkstra +head

 const int N=;
struct rec
{
int v,w;//v代表所连的值,W代表权值
}; vector<rec> edge[N*N];
int n,st,ed;
long long dis[N*N];
bool vis[N*N]; struct cmp
{
bool operator()(int a,int b)
{
return dis[a]>dis[b];
}
}; void Dijkstra()
{
priority_queue<int,vector<int>,cmp> Q;
memset(dis,-,sizeof(dis));
memset(vis,,sizeof(vis));
int i,u,v;
Q.push(st);
dis[st]=;
while(!Q.empty())
{
u=Q.top();
Q.pop();
vis[u]=;
if(u==st)
break;
if(dis[v]==- || dis[v]<dis[u]*edge[u][i].w)
{
dis[v]=dis[u]*edge[u][i].w;
if(!vis[v])
{
vis[v]=;
Q.push(v);
}
}
}
}
}
for(i=; i<edge[u].size(); i++)
{
v=edge[u][i].v;
if(dis[v]==- || dis[v]<dis[u]*edge[u][i].w)
{
dis[v]=dis[u]*edge[u][i].w;
if(!vis[v])
{
vis[v]=;
Q.push(v);
}
}
}
}
}