poj 2387 Til the Cows Come Home(最短路径)

/*
dijkstra
Memory 4108K
Time   125MS
*/
#include <iostream>
#include <stdio.h>
using namespace std;
#define inf 1<<29
#define MAXV 1005

int map[MAXV][MAXV];
int n,m;

void dijkstra()
{
int i,j,min,v;
int d[MAXV];
bool vis[MAXV];

for(i=1; i<=n; i++)
{
vis[i]=0;
d[i]=map[1][i];
}

for(i=1; i<=n; i++)
{
min=inf;
for(j=1; j<=n; j++)
if(!vis[j] && d[j]<min)
{
v=j;
min=d[j];
}
vis[v]=1;

for(j=1; j<=n; j++)
if(!vis[j] && d[j]>map[v][j]+d[v])
d[j]=map[v][j]+d[v];
}
printf("%d\n",d
);
}

int main()
{
int i,j,a,b,c;
while(~scanf("%d%d",&m,&n))
{
for(i=1; i<=n; i++)
for(j=1; j<=n; j++)
if(i==j)
map[i][i]=0;
else map[i][j]=map[j][i]=inf;

for(i=1; i<=m; i++)
{
scanf("%d%d%d",&a,&b,&c);
if(map[a][b]>c) map[a][b]=map[b][a]=c;
}
dijkstra();
}
return 0;
}

/*
Memory 188K
Time   16MS
其实bellman-ford在某些时候还是很快滴
*/
#include <iostream>
#include <stdio.h>
using namespace std;
#define inf 1<<29
#define MAXM 2005
#define MAXV 1005

typedef struct{
int a,b,w;
}Edge;

Edge edge[MAXM];
int n,m;

void bellman_ford(){
int i,j;
int d[MAXV];
for(i=2;i<=n;i++) d[i]=inf;
d[1]=0;

for(i=1;i<=n;i++){
for(j=1;j<=m;j++){
if(d[edge[j].a]>edge[j].w+d[edge[j].b]) d[edge[j].a]=edge[j].w+d[edge[j].b];
if(d[edge[j].b]>edge[j].w+d[edge[j].a]) d[edge[j].b]=edge[j].w+d[edge[j].a];
}
}
printf("%d\n",d
);
}

int main(){
int i,a,b,c;
while(~scanf("%d%d",&m,&n)){
for(i=1;i<=m;i++){
scanf("%d%d%d",&a,&b,&c);
edge[i].a=a;
edge[i].b=b;
edge[i].w=c;
}
bellman_ford();
}
return 0;
}

/*
spfa
Memory 256K
Time   32MS
*/
#include <iostream>
#include <stdio.h>
#include <queue>
using namespace std;
#define inf 1<<29
#define MAXM 4005
#define MAXV 1005

typedef struct{
int a,b,w,next;
}Edge;

Edge edge[MAXM];
int n,m,headlist[MAXV];

void spfa(){
int i,d[MAXV],v,vis[MAXV];
queue <int>q;
for(i=2;i<=n;i++){
d[i]=inf;
vis[i]=0;
}
d[1]=0;
vis[1]=1;
q.push(1);
while(!q.empty()){
v=q.front();q.pop();
vis[v]=0;

for(i=headlist[v];i!=-1;i=edge[i].next)
if(d[v]+edge[i].w<d[edge[i].b]){
d[edge[i].b]=d[v]+edge[i].w;
if(!vis[edge[i].b]){
vis[edge[i].b]=1;
q.push(edge[i].b);
}
}
}
printf("%d\n",d
);
}

int main(){
int i,a,b,c;
while(~scanf("%d%d",&m,&n)){
for(i=1;i<=n;i++) headlist[i]=-1;
for(i=1;i<=2*m;i+=2){
scanf("%d%d%d",&a,&b,&c);
edge[i].a=a;
edge[i].b=b;
edge[i].w=c;
edge[i].next=headlist[a];
headlist[a]=i;
edge[i+1].a=b;
edge[i+1].b=a;
edge[i+1].w=c;
edge[i+1].next=headlist[b];
headlist[b]=i+1;
}
spfa();
}
return 0;
}