Submission #258912

#	Time	Username	Problem	Language	Result	Execution time	Memory
258912		easrui	Graph (BOI20_graph)	C++14	100 / 100	244 ms	26348 KiB

Graph

#include <bits/stdc++.h>
using namespace std;
#define all(x) (x).begin(), (x).end()
const int MN = 2e5+5;

//start at 1:43

int E[MN],dep[MN],cnt[MN],par[MN],odd[MN],cur;
double C[MN],sum[MN],val[MN];
vector<int> G[MN],group;
vector<double> tmp;
bool vis[MN],fail;

void dfs(int s)
{
	vis[s] = 1;
	for(int d:G[s]){
		int e = E[d]-s;
		if(vis[e]){
			if(dep[e]<dep[s]) continue;
			if((dep[e]-dep[s])%2){
				if( (cnt[e]-cnt[par[s]]) - (cnt[par[e]]-cnt[s]) != C[d]-1) fail = 1;
			}
			else{
				if(odd[cur]) continue;
				odd[cur] = s;
				val[s] = (-sum[e]+sum[s]+sum[par[e]]-sum[par[s]]+C[d])/2.0;
			}
		}
		else{
			par[e] = s;
			dep[e] = dep[s]+1;
			cnt[e] = cnt[par[s]];
			if(C[d]==2) cnt[e]++;
			sum[e] = sum[par[s]]+C[d];
			dfs(e);
		}
	}
}

void solve(int s)
{
	group.push_back(s);
	vis[s] = 1;
	for(int d:G[s]){
		int e = E[d]-s;
		if(vis[e]){
			if(odd[cur]&&val[s]+val[e]!=C[d]) fail = 1;
		}
		else{
			val[e] = C[d]-val[s];
			solve(e);
		}
	}
	tmp.push_back(dep[s]%2 ? -val[s] : val[s]);
}

int N,M;

int main()
{
    ios_base::sync_with_stdio(0),cin.tie(0);
    cin >> N >> M;
    for(int i=0; i<M; i++){
    	int a,b;
    	cin >> a >> b >> C[i];
    	E[i] = a+b;
    	G[a].push_back(i);
    	G[b].push_back(i);
    }
    for(int i=1; i<=N; i++){
    	if(vis[i]) continue;
    	cur = i;
    	dfs(i);
    }
    fill(vis,vis+N+1,0);

    for(int i=1; i<=N; i++){
    	if(vis[i]) continue;
    	cur = i;
		group.clear();
		tmp.clear();
    	if(odd[i]) solve(odd[i]);
    	else{
    	    solve(i);
		    sort(all(tmp));
		    double x = -tmp[group.size()/2];
		    for(int s:group){
		    	if(dep[s]%2) val[s] -= x;
		    	else val[s] += x;
		    }
    	}
    }

    fixed(cout);
    cout.precision(1);
    if(fail) cout << "NO";
    else{
    	cout << "YES\n";
    	for(int i=1; i<=N; i++) cout << val[i] << ' ';
	}
}

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