并查集:
#include <bits/stdc++.h>
using namespace std;
const int maxn=10000+10;
int fa[maxn];
int find(int x){
if(fa[x]==x)
return x;
else
return fa[x]=find(fa[x]);
}
int main(){
int n,m;
cin>>n>>m;
for(int i=1;i<=n;i++)
fa[i]=i;
for(int i=1;i<=m;i++){
int x,y,z;
cin>>z>>x>>y;
if(z==1)
fa[find(x)]=find(y);
else{
if(find(x)==find(y))
cout<<"Y"<<endl;
else
cout<<"N"<<endl;
}
}
return 0;
}
单源最短路:
#include <bits/stdc++.h>
using namespace std;
const int maxn=500000+10,maxm=10000+10,INF=2147483647;
bool visit[maxm];
int headd[maxm],cnt,n,m,s,a,b,c;
int dis[maxm];
struct Edge{
int z;
int val;
int nexty;
}edge[maxn];
void add(int a,int b,int c){
cnt++;
edge[cnt].z=b;
edge[cnt].val=c;
edge[cnt].nexty=headd[a];
headd[a]=cnt;
}
int main(){
cin>>n>>m>>s;
for(int i=1;i<=n;i++)
dis[i]=INF;
for(int i=1;i<=m;i++){
cin>>a>>b>>c;
add(a,b,c);
}
int curr=s;
dis[s]=0;
long long minn=INF;
while(!visit[curr]){
visit[curr]=1;
for(int i=headd[curr];i;i=edge[i].nexty)
if(!visit[edge[i].z]&&dis[edge[i].z]>dis[curr]+edge[i].val)
dis[edge[i].z]=dis[curr]+edge[i].val;
minn=INF;
for(int i=1;i<=n;i++)
if(!visit[i]&&minn>dis[i]){
minn=dis[i];
curr=i;
}
}
for(int i=1;i<=n;i++)
cout<<dis[i]<<" ";
return 0;
}