Submission #1030567

#	Time	Username	Problem	Language	Result	Execution time	Memory
1030567		12345678	Graph (BOI20_graph)	C++17	0 / 100	1 ms	2652 KiB

Graph

#include <bits/stdc++.h>

using namespace std;

const int nx=1e5+5;

int n, m, u, v, w, a[nx], b[nx], f, vs[nx];
double res[nx];
vector<tuple<int, int, int>> d[nx];
vector<int> comp;
set<double> s;

void dfs(int u, int p)
{
    vs[u]=1;
    comp.push_back(u);
    for (auto [v, w, idx]:d[u])
    {
        if (idx==p) continue;
        if (vs[v])
        {
            int sma=a[u]+a[v], smb=b[u]+b[v];
            if (sma==0&&b[u]+b[v]==w) continue;
            else if (sma==0&&b[u]+b[v]!=w)
            {
                f=1;
                break;
            }
            s.insert(((double)(w-smb))/((double)sma));
        }
        else
        {
            a[v]=-a[u];
            b[v]=w-b[u];
            dfs(v, idx);
        }
    }
}
int main()
{
    cin.tie(NULL)->sync_with_stdio(false);
    cin>>n>>m;
    for (int i=1; i<=m; i++) cin>>u>>v>>w, d[u].push_back({v, w, i}), d[v].push_back({u, w, i});
    for (int i=1; i<=n; i++)
    {
        if (!vs[i])
        {
            comp.clear();
            s.clear();
            a[i]=1;
            dfs(i, -1);
            if (s.size()>1) f=1;
            else if (s.size()==1)
            {
                double vl=*s.begin();
                for (auto x:comp) res[x]=a[x]*vl+b[x];
            }
            else
            {
                vector<pair<double, int>> v;
                for (auto x:comp) if (a[x]!=0) v.push_back({(double)(-b[x])/(double)a[x], x});
                sort(v.begin(), v.end());
                vector<int> qs(v.size());
                for (int i=0; i<v.size(); i++)
                {
                    qs[i]=abs(a[v[i].second]);
                    if (i!=0) qs[i]+=qs[i-1];
                }
                double t=0;
                long long cnt, idx;
                if (!v.empty())
                {
                    cnt=(qs[v.size()-1]+1)/2;
                    idx=lower_bound(qs.begin(), qs.end(), t)-qs.begin();
                    t=v[idx].first;
                }
                for (auto x:comp) res[x]=(double)t*a[x]+(double)b[x];
            }
        }
    }
    if (f) return cout<<"NO\n", 0;
    cout<<"YES\n";
    for (int i=1; i<=n; i++) cout<<setprecision(8)<<res[i]<<' ';
}

Compilation message (stderr)

Graph.cpp: In function 'int main()':
Graph.cpp:64:32: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<double, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   64 |                 for (int i=0; i<v.size(); i++)
      |                               ~^~~~~~~~~
Graph.cpp:70:27: warning: variable 'cnt' set but not used [-Wunused-but-set-variable]
   70 |                 long long cnt, idx;
      |                           ^~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 12
• Subtask 3: 0 / 17
• Subtask 4: 0 / 24
• Subtask 5: 0 / 42