HDU 1874 畅通工程续 SPFA || dijkstra||floyd

#include<cstdio>
#include<cstring>
const int MAXN=200+10;
const int INF=1000000;
int n,m,map[MAXN][MAXN],dis[MAXN];
bool vis[MAXN];

void dijkstra(int s)
{
memset(vis,0,sizeof(vis));
int cur=s;
dis[cur]=0;
vis[cur]=1;
for(int i=0;i<n;i++)
{
for(int j=0;j<n;j++)
if(!vis[j] && dis[cur] + map[cur][j] < dis[j])
dis[j]=dis[cur] + map[cur][j] ;

int mini=INF;
for(int j=0;j<n;j++)
if(!vis[j] && dis[j] < mini)
mini=dis[cur=j];
vis[cur]=true;
}

}
int main()
{
while(~scanf("%d%d",&n,&m))
{
for(int i=0;i<n;i++)
{
dis[i]=INF;
for(int j=0;j<n;j++)
map[i][j]=INF;
}
for(int i=0;i<m;i++)
{
int from,to,val;
scanf("%d%d%d",&from,&to,&val);
if(map[from][to] > val)
map[to][from]=map[from][to]=val;
}
int s,t;
scanf("%d%d",&s,&t);
dijkstra(s);
if(dis[t]==INF)
printf("-1\n");
else
printf("%d\n",dis[t]);
}
return 0;

}

#include<cstdio>
#include<cstring>
#include<queue>
using namespace std;
const int MAXN=200+10;
const int MAXM=40000+10;
const int INF=1000000;
int n,m,dis[MAXN],head[MAXN],len;
bool vis[MAXN];

struct edge
{
int to,val,next;
}e[MAXM];

void add(int from,int to,int  val)
{
e[len].to=to;
e[len].val=val;
e[len].next=head[from];
head[from]=len++;
}
struct point
{
int val,id;
point(int id,int val):id(id),val(val){}
bool operator <(const point &x)const{
return val>x.val;
}
};
void dijkstra(int s)
{
memset(vis,0,sizeof(vis));
for(int i=0;i<n;i++)
dis[i]=INF;

priority_queue<point> q;
q.push(point(s,0));
dis[s]=0;
while(!q.empty())
{
int cur=q.top().id;
q.pop();
if(vis[cur]) continue;
vis[cur]=true;
for(int i=head[cur];i!=-1;i=e[i].next)
{
int id=e[i].to;
if(!vis[id] && dis[cur]+e[i].val < dis[id])
{
dis[id]=dis[cur]+e[i].val;
q.push(point(id,dis[id]));
}
}
}
}
int main()
{
while(~scanf("%d%d",&n,&m))
{
len=0;
memset(head,-1,sizeof(head));

for(int i=0;i<m;i++)
{
int from,to,val;
scanf("%d%d%d",&from,&to,&val);
add(from,to,val);
add(to,from,val);
}

int s,t;
scanf("%d%d",&s,&t);
dijkstra(s);
if(dis[t]==INF)
printf("-1\n");
else
printf("%d\n",dis[t]);
}
return 0;

}

#include<cstdio>
#include<queue>
using namespace std;
const int INF=1000000;
const int MAXN=200+10;
int n,m;
int map[MAXN][MAXN];
int dis[MAXN];
void SPFA(int s)
{
for(int i=0;i<n;i++)
dis[i]=INF;

bool vis[MAXN]={0};

vis[s]=true;
dis[s]=0;

queue<int> q;
q.push(s);
while(!q.empty())
{
int cur=q.front();
q.pop();
vis[cur]=false;
for(int i=0;i<n;i++)
{
if(dis[cur] + map[cur][i] < dis[i])
{
dis[i]=dis[cur] + map[cur][i];
if(!vis[i])
{
q.push(i);
vis[i]=true;
}
}
}
}
}
int main()
{
while(~scanf("%d%d",&n,&m))
{
for(int i=0;i<n;i++)
for(int j=0;j<n;j++)
map[i][j]=INF;

for(int i=0;i<m;i++)
{
int from,to,dis;
scanf("%d%d%d",&from,&to,&dis);
if(map[from][to]>dis)
map[from][to]=map[to][from]=dis;
}
int s,t;
scanf("%d%d",&s,&t);
SPFA(s);
if(dis[t]==INF)
puts("-1");
else
printf("%d\n",dis[t]);
}
return 0;
}

#include<cstdio>
#include<cstring>
#include<queue>
using namespace std;
const int MAXN=200+10;
const int MAXM=40000+10;
const int INF=1000000;
int n,m,dis[MAXN],head[MAXN],len;
bool vis[MAXN];

struct edge
{
int to,val,next;
}e[MAXM];

void add(int from,int to,int  val)
{
e[len].to=to;
e[len].val=val;
e[len].next=head[from];
head[from]=len++;
}
void spfa(int s)
{
memset(vis,0,sizeof(vis));
for(int i=0;i<n;i++)
dis[i]=INF;

queue<int> q;
q.push(s);
vis[s]=true;
dis[s]=0;
while(!q.empty())
{
int cur=q.front();
q.pop();
vis[cur]=false;
for(int i=head[cur];i!=-1;i=e[i].next)
{
int id=e[i].to;
if(dis[id] > dis[cur]+e[i].val)
{
dis[id] = dis[cur] + e[i].val;
if(!vis[id])
{
vis[id]=true;
q.push(id);
}
}
}
}
}
int main()
{
while(~scanf("%d%d",&n,&m))
{
len=0;
memset(head,-1,sizeof(head));

for(int i=0;i<m;i++)
{
int from,to,val;
scanf("%d%d%d",&from,&to,&val);
add(from,to,val);
add(to,from,val);
}

int s,t;
scanf("%d%d",&s,&t);
spfa(s);
if(dis[t]==INF)
printf("-1\n");
else
printf("%d\n",dis[t]);
}
return 0;

}

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int MAXN=200+10;
const int INF=1000000;
int n,m,dis[MAXN][MAXN];

void floyd()
{
for(int k=0;k<n;k++)
for(int i=0;i<n;i++)
for(int j=0;j<n;j++)
dis[i][j]=min(dis[i][j],dis[i][k]+dis[k][j]);
}
int main()
{
while(~scanf("%d%d",&n,&m))
{
for(int i=0;i<n;i++)
for(int j=0;j<n;j++)
dis[i][j]=INF;

for(int i=0;i<m;i++)
{
int from,to,val;
scanf("%d%d%d",&from,&to,&val);
if(dis[from][to] > val)
dis[to][from]=dis[from][to]=val;
}
int s,t;
scanf("%d%d",&s,&t);
if(s==t)
{
printf("0\n");
continue;
}
floyd();
if(dis[s][t]==INF)
printf("-1\n");
else
printf("%d\n",dis[s][t]);
}
return 0;

}