Submission #1287936

#	Time	Username	Problem	Language	Result	Execution time	Memory
1287936		Hamed_Ghaffari	Graph (BOI20_graph)	C++20	100 / 100	136 ms	20360 KiB

Graph

#include <bits/stdc++.h>
using namespace std;

using pii = pair<int, int>;

#define X first
#define Y second
#define SZ(x) int(x.size())
#define all(x) x.begin(), x.end()

const int MXN = 2e5+5;

int n, m, fr[MXN], to[MXN], w[MXN], rt[MXN];
vector<int> g[MXN], roots, vec[MXN];
pii val[MXN];
bool vis[MXN], mark[MXN], fnd[MXN];
int xf[MXN];

void dfs(int v) {
    vec[rt[v]].push_back(val[v].Y*(val[v].X>0 ? -1 : 1));
    vis[v] = 1;
    for(int i : g[v]) {
        int u = v^fr[i]^to[i];
        if(vis[u]) continue;
        val[u].X = -val[v].X;
        val[u].Y = -val[v].Y+w[i];
        mark[i] = 1;
        rt[u] = rt[v];
        dfs(u);
    }
}

int sgn(int x) { return x>0 ? 1 : (x<0 ? -1 : 0); }

int32_t main() {
    cin.tie(0); cout.tie(0); ios_base::sync_with_stdio(0);
    cin >> n >> m;
    for(int i=1; i<=m; i++) {
        cin >> fr[i] >> to[i] >> w[i]; w[i] *= 2;
        g[fr[i]].push_back(i);
        g[to[i]].push_back(i);
    }
    for(int root=1; root<=n; root++) if(!vis[root]) {
        val[root] = {root, 0};
        rt[root] = root;
        dfs(root);
        roots.push_back(root);
    }
    for(int i=1; i<=m; i++) if(!mark[i]) {
        if(val[fr[i]].X+val[to[i]].X) {
            int y = (w[i]-val[fr[i]].Y-val[to[i]].Y) / (sgn(val[fr[i]].X) + sgn(val[to[i]].X));
            if(!fnd[rt[fr[i]]] || (fnd[rt[fr[i]]] && y==xf[rt[fr[i]]])) {
                fnd[rt[fr[i]]] = 1;
                xf[rt[fr[i]]] = y;
            }
            else {
                cout << "NO\n";
                return 0;
            }
        }
        else if(val[fr[i]].Y+val[to[i]].Y!=w[i]) {
            cout << "NO\n";
            return 0;
        }
    }
    cout << "YES\n";
    for(int root : roots) if(!fnd[root]) {
        sort(all(vec[root]));
        xf[root] = vec[root][SZ(vec[root])/2];
    }   
    for(int i=1; i<=n; i++) {
        int v = sgn(val[i].X)*xf[rt[i]] + val[i].Y;
        if(v<0) cout << '-', v = -v;
        cout << v/2;
        if(v%2) cout << ".5";
        cout << ' ';
    }
    cout << '\n';
    return 0;
}

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