noip_最后一遍_2-图论部分

Posted 2021-01-17 iboom

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大体按照数学图论 dp 数据结构这样的顺序

模板集这个真的只有模板了………………

·spfa

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 #define ll long long
 4 #define maxn 100005
 5 ll n,m,k,l,a,b,c,d[maxn],s,visit[maxn];
 6 struct edge{int from,to,val;};
 7 vector<int>g[maxn];vector<edge>edges;
 8 void add_edge(int f,int t,int v){
 9     g[f].push_back(k);edges.push_back({f,t,v});k+=1;
10 }void spfa(int s){
11     for(int i=1;i<=n;i++)d[i]=2147483647;queue<int>q;q.push(s);
12     visit[s]=1,d[s]=0;
13     while(!q.empty()){int u=q.front();q.pop();visit[u]=0;
14         for(int i=0;i<g[u].size();i++){edge &e=edges[g[u][i]];
15             if(d[e.to]>d[u]+e.val){d[e.to]=d[u]+e.val;
16                 if(!visit[e.to])q.push(e.to),visit[e.to]=1;
17             }
18         }
19     }
20 }
21 int main(){
22     cin>>n>>m>>s;for(int i=1;i<=m;i++)cin>>a>>b>>c,add_edge(a,b,c);spfa(s);
23     for(int i=1;i<=n;i++)cout<<d[i]<<" ";
24 }

View Code

·dj

 1 #include<bits/stdc++.h>
 2 using namespace std;
 3 #define ll long long
 4 #define maxn 100005
 5 
 6 ll n,m,k,l,a,b,c,d[maxn],s,visit[maxn];
 7 struct edge{int from,to,val;};
 8 vector<int>g[maxn];vector<edge>edges;
 9 void add_edge(int f,int t,int v){
10     g[f].push_back(k);edges.push_back({f,t,v});k+=1;
11 }
12 
13 struct node{int u,d;
14     bool operator <(node b)const{
15         return d>b.d; 
16     }
17 };
18 void dj(int s){
19     for(int i=1;i<=n;i++)d[i]=2147483647;priority_queue<node>q;q.push({s,0});
20     visit[s]=1,d[s]=0;
21     while(!q.empty()){int u=q.top().u;q.pop();visit[u]=0;
22         for(int i=0;i<g[u].size();i++){edge &e=edges[g[u][i]];
23             if(d[e.to]>d[u]+e.val){d[e.to]=d[u]+e.val;
24                 if(!visit[e.to])q.push({e.to,d[e.to]}),visit[e.to]=1;
25             }
26         }
27     }
28 }
29 
30 int main(){
31     cin>>n>>m>>s;
32     for(int i=1;i<=m;i++)scanf("%lld%lld%lld",&a,&b,&c),add_edge(a,b,c);
33     dj(s);for(int i=1;i<=n;i++)printf("%lld ",d[i]);
34     return 0;
35 }