Acwing 图论进阶打卡

1129. 热浪

https://www.acwing.com/problem/content/1131/

#include<iostream>
#include<algorithm>
#include<cstdio>
#include<vector>
#include<queue>
#include<stack>
#include<cstring>
#include<unordered_map>
using namespace std;
typedef long long LL;
const int N=2510,M=6210*2;
int h[N],w[M],e[M],ne[M],idx;
int n,m,TS,TE;
int dist[N],st[N];
void add(int a,int b,int c){
    e[idx]=b;
    w[idx]=c;
    ne[idx]=h[a];
    h[a]=idx++;
}
void spfa(){
    queue<int>q;
    q.push(TS);
    st[TS]=1;
    dist[TS]=0;
    while(q.size()){
        int k=q.front();
        st[k]=0;
        q.pop();
        for(int i=h[k];i!=-1;i=ne[i]){
            int j=e[i];
            if(dist[j]>dist[k]+w[i]){
                dist[j]=dist[k]+w[i];
                if(!st[j]){
                    st[j]=1;
                    q.push(j);
                }
            }
        }
    }
}
int main(){
    cin>>n>>m>>TS>>TE;
    memset(h,-1,sizeof h);
    memset(dist,0x3f,sizeof dist);
    for(int i=0;i<m;i++){
        int a,b,c;
        cin>>a>>b>>c;
        add(a,b,c);
        add(b,a,c);
    }
    spfa();
    cout<<dist[TE]<<endl;
  return 0;
}
//  freopen("testdata.in", "r", stdin);

1128. 信使

https://www.acwing.com/problem/content/1130/

#include<iostream>
#include<algorithm>
#include<cstdio>
#include<vector>
#include<queue>
#include<stack>
#include<cstring>
#include<unordered_map>
using namespace std;
typedef long long LL;
const int N=105,M=205*2;
int h[N],w[M],e[M],ne[M],idx;
int n,m;
int dist[N],st[N];
void add(int a,int b,int c){
    e[idx]=b;
    w[idx]=c;
    ne[idx]=h[a];
    h[a]=idx++;
}
void spfa(){
    queue<int>q;
    q.push(1);
    dist[1]=0;
    while(q.size()){
        int k=q.front();
        st[k]=0;
        q.pop();
        for(int i=h[k];i!=-1;i=ne[i]){
            int j=e[i];
            if(dist[j]>dist[k]+w[i]){
                dist[j]=dist[k]+w[i];
                if(!st[j]){
                    st[j]=1;
                    q.push(j);
                }
            }
        }
    }
}
int main(){
    cin>>n>>m;
    memset(h,-1,sizeof h);
    memset(dist,0x3f,sizeof dist);
    for(int i=0;i<m;i++){
        int a,b,c;
        cin>>a>>b>>c;
        add(a,b,c);
        add(b,a,c);
    }
    spfa();
    int res=0;
    for(int i=1;i<=n;i++){
        res=max(res,dist[i]);
    }
    if(res==0x3f3f3f3f) puts("-1");
    else cout<<res<<endl;
  return 0;
}
//  freopen("testdata.in", "r", stdin);

1135. 新年好

https://www.acwing.com/problem/content/1137/
记住阿杰算法第一次放入队列的那个值没有修改st操作!!!

#include<iostream>
#include<algorithm>
#include<cstdio>
#include<vector>
#include<queue>
#include<stack>
#include<cstring>
#include<unordered_map>
using namespace std;
typedef long long LL;
typedef pair<int,int>PII;
const int N=5e4+10,M=2e5+10;
int h[N],w[M],e[M],ne[M],idx;
int n,m;
int source[6],dist[6][N],st[N];
void add(int a,int b,int c){
    e[idx]=b;
    w[idx]=c;
    ne[idx]=h[a];
    h[a]=idx++;
}
void dijkstra(int start,int dist[]){
    memset(dist,0x3f,N*4);
    memset(st,0,sizeof st);
    priority_queue<PII,vector<PII>,greater<PII>>heap;
    heap.push({0,start});
    dist[start]=0;
    while(heap.size()){
        auto temp=heap.top();
        heap.pop();
        int ver=temp.second;
        if(st[ver]) continue;
        st[ver]=1;
        for(int i=h[ver];i!=-1;i=ne[i]){
            int j=e[i];
            if(dist[j]>dist[ver]+w[i]){
                dist[j]=dist[ver]+w[i];
                heap.push({dist[j],j});
            }
        }
    }
}
int dfs(int u,int start,int distance){
    if(u>5) return distance;
    int res=0x3f3f3f3f;
    for(int i=1;i<=5;i++){
        if(!st[i]){
            int next=source[i];
            st[i]=1;
            res=min(res,dfs(u+1,i,distance+dist[start][next]));
            st[i]=0;
        }
    }
    return res;
}
int main(){
    cin>>n>>m;
    source[0]=1;
    memset(h,-1,sizeof h);
    memset(dist,0x3f,sizeof dist);
    for(int i=1;i<=5;i++){
        cin>>source[i];
    }
    for(int i=0;i<m;i++){
        int a,b,c;
        cin>>a>>b>>c;
        add(a,b,c);
        add(b,a,c);
    }
    for(int i=0;i<6;i++){
        dijkstra(source[i],dist[i]);
    }
    memset(st,0,sizeof st);
    cout<<dfs(1,0,0)<<endl;
  return 0;
}
//  freopen("testdata.in", "r", stdin);