【专题复习2：图的遍历】1013、1021、1034、1076

1013

1013

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#include <bits/stdc++.h>

using namespace std;
vector<int> G[10010];
bool vis[10010];
int curpoint;
void dfs(int index)
{
    if(index==curpoint) return;
    vis[index]=true;
    for(int i=0;i<G[index].size();i++)
        if(!vis[G[index][i]])
            dfs(G[index][i]);
}
int main()
{
    #ifdef ONLINE_JUDGE
#else
    freopen("1.txt", "r", stdin);
#endif
    int n,m,k,a,b;
    cin>>n>>m>>k;
    for(int i=0;i<m;i++){
        cin>>a>>b;
        G[a].push_back(b);
        G[b].push_back(a);
    }
    for(int i=0;i<k;i++){
        cin>>curpoint;
        memset(vis,false,sizeof(vis));
        int block=0;
        for(int j=1;j<=n;j++){
            if(j!=curpoint&&vis[j]==false){
                dfs(j);
                block++;
            }
        }
        cout<<block-1<<endl;
    }
    return 0;
}

1021

1021

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#include <bits/stdc++.h>

using namespace std;
vector<int> G[10010];
bool vis[10010];
int maxdepth;
set<int> temp,ans;
void dfs(int index,int depth)
{
    if(depth>maxdepth){
        temp.clear();
        maxdepth=depth;
        temp.insert(index);
    }else if(depth==maxdepth)
        temp.insert(index);
    vis[index]=true;
    for(int i=0;i<G[index].size();i++)
        if(!vis[G[index][i]])
            dfs(G[index][i],depth+1);
}
int main()
{
    #ifdef ONLINE_JUDGE
#else
    freopen("1.txt", "r", stdin);
#endif
    int n,a,b,cnt=0,s1=0;
    cin>>n;
    for(int i=0;i<n-1;i++){
        cin>>a>>b;
        G[a].push_back(b);
        G[b].push_back(a);
    }
    for(int i=1;i<=n;i++){
        if(vis[i]==false){
            dfs(i,1);
            cnt++;
        }
    }
    if(cnt>=2)
        printf("Error: %d components\n",cnt);
    else{
        ans=temp;
        temp.clear();
        fill(vis,vis+10010,false);
        auto it=ans.begin();
        dfs(*it,1);
        for(auto it=temp.begin();it!=temp.end();it++)
            ans.insert(*it);
        for(auto it=ans.begin();it!=ans.end();it++)
            cout<<*it<<endl;
    }
    return 0;
}

1034

1034

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#include <bits/stdc++.h>

using namespace std;
int G[2010][2010],weight[2010],k;
bool vis[2010];
map<string,int> strToInt,ans;
map<int,string> intToStr;
int id=1;
int change(string s)
{
    if(strToInt[s]==0){
        strToInt[s]=id;
        intToStr[id]=s;
        return id++;
    }else{
        return strToInt[s];
    }
}
void dfs(int u,int &head,int &numMember,int &totalweight)
{
    vis[u]=true;
    numMember++;
    if(weight[u]>weight[head])
        head=u;
    for(int v=1;v<id;v++){
        if(G[u][v]>0){
            totalweight+=G[u][v];
            G[u][v]=G[v][u]=0;
            if(vis[v]==false)
                dfs(v,head,numMember,totalweight);
        }
    }
}
void dfsTrave()
{
    for(int i=1;i<id;i++){
        if(vis[i]==false){
            int head=i,numMember=0,totalweight=0;
            dfs(i,head,numMember,totalweight);
            if(numMember>2&&totalweight>k)
                ans[intToStr[head]]=numMember;
        }
    }
}
int main()
{
    #ifdef ONLINE_JUDGE
#else
    freopen("1.txt", "r", stdin);
#endif
    int n,a,b,w;
    string s1,s2;
    cin>>n>>k;
    for(int i=0;i<n;i++){
        cin>>s1>>s2>>w;
        int a=change(s1);
        int b=change(s2);
        weight[a]+=w;
        weight[b]+=w;
        G[a][b]+=w;
        G[b][a]+=w;
    }
    dfsTrave();
    cout<<ans.size()<<endl;
    for(auto it=ans.begin();it!=ans.end();it++)
        cout<<it->first<<" "<<it->second<<endl;
    return 0;
}

1076

1076

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#include <bits/stdc++.h>

using namespace std;
struct node
{
    int id,layer;
};
int n,l;
vector<int> v[1010];
int bfs(node tnode)
{
    queue<node> q;
    q.push(tnode);
    bool vis[1010]={false};
    vis[tnode.id]=true;
    int cnt=0;
    while(!q.empty()){
        node top=q.front();
        q.pop();
        int topid=top.id;
        for(int i=0;i<v[topid].size();i++){
            int nextid=v[topid][i];
            if(vis[nextid]==false&&top.layer<l){
                node next={nextid,top.layer+1};
                q.push(next);
                vis[next.id]=true;
                cnt++;
            }
        }
    }
    return cnt;
}
int main()
{
    #ifdef ONLINE_JUDGE
#else
    freopen("1.txt", "r", stdin);
#endif
    int num,temp;
    cin>>n>>l;
    for(int i=1;i<=n;i++){
        cin>>num;
        for(int j=0;j<num;j++){
            cin>>temp;
            v[temp].push_back(i);
        }
    }
    int k,tid;
    cin>>k;
    for(int i=0;i<k;i++){
        cin>>tid;
        node tnode={tid,0};
        cout<<bfs(tnode)<<endl;
    }
    return 0;
}