Submission #745424

#	Time	Username	Problem	Language	Result	Execution time	Memory
745424		MilosMilutinovic	Graph (BOI20_graph)	C++14	100 / 100	144 ms	23124 KiB

Graph

#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 10;
int n, m, coeff[N], delta[N];
double ans[N], val;
vector<pair<int, int>> g[N];
vector<int> comp;
bool ok = true, found, was[N];
void dfs(int x) {
    was[x] = true;
    comp.push_back(x);
    for (auto& p : g[x]) {
        int y = p.first;
        int w = p.second;
        if (was[y]) {
            if (-coeff[y] == coeff[x]) {
                ok = (ok & ((w - delta[y]) == delta[x]));
            } else {
                found = true;
                val = (w - delta[x] - delta[y]) * 1.0 / (coeff[y] + coeff[x]);
            }
            continue;
        }
        coeff[y] = -coeff[x];
        delta[y] = w - delta[x];
        dfs(y);
    }
}
int main() {
    scanf("%d%d", &n, &m);
    for (int i = 1; i <= m; i++) {
        int a, b, c;
        scanf("%d%d%d", &a, &b, &c);
        g[a].emplace_back(b, c);
        g[b].emplace_back(a, c);
    }
    for (int i = 1; i <= n; i++) if (!was[i]) {
        coeff[i] = 1;
        delta[i] = 0;
        comp.clear();
        found = false;
        dfs(i);
        if (!ok) break;
        if (found) {
            for (int x : comp) ans[x] = val * coeff[x] + delta[x];
        } else {
            vector<int> f;
            for (int x : comp) f.push_back(delta[x] * coeff[x]);
            sort(f.begin(), f.end());
            val = -f[(int) f.size() / 2];
            for (int x : comp) ans[x] = val * coeff[x] + delta[x];
        }
    }
    for (int i = 1; i <= n; i++) {
        for (auto& p : g[i]) {
            if (ans[i] + ans[p.first] != p.second * 1.0) ok = false;
        }
    }
    if (!ok) { printf("NO"); return 0; }
    printf("YES\n");
    for (int i = 1; i <= n; i++) printf("%0.5lf ", ans[i]);
    return 0;
}

Compilation message (stderr)

Graph.cpp: In function 'int main()':
Graph.cpp:30:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |     scanf("%d%d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~
Graph.cpp:33:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |         scanf("%d%d%d", &a, &b, &c);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~~

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