Submission #490306

#	Time	Username	Problem	Language	Result	Execution time	Memory
490306		JerryLiu06	Pipes (BOI13_pipes)	C++17	74.07 / 100	79 ms	11844 KiB

pipes

// https://oj.uz/problem/view/BOI13_pipes
 
#include <bits/stdc++.h>
 
using namespace std;
 
using ll = long long;
using ld = long double;
using db = double;
using str = string;
 
using pi = pair<int, int>;
using pl = pair<ll, ll>;
using pd = pair<db, db>;
 
using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>;
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>;
using vpd = vector<pd>;
 
#define FASTIO ios_base::sync_with_stdio(false); cin.tie(0);
#define FASTIOF ios_base::sync_with_stdio(false); fin.tie(0);
 
#define mp make_pair
#define f first
#define s second
 
#define sz(x) (int)(x).size()
#define bg(x) begin(x)
#define all(x) bg(x), end(x)
#define sor(x) sort(all(x))
#define rsz resize
#define ins insert 
#define ft front()
#define bk back()
#define pb push_back
#define pf push_front
 
#define lb lower_bound
#define ub upper_bound
 
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define F0R(i, a) FOR(i, 0, a)
#define ROF(i, a, b) for (int i = (b) - 1; i >= (a); i--)
#define R0F(i, a) ROF(i, 0, a)
#define EACH(a, x) for (auto& a : x)
 
ll cdiv(ll a, ll b) { return a / b + ((a ^ b) > 0 && a % b); }
ll fdiv(ll a, ll b) { return a / b - ((a ^ b) < 0 && a % b); }
 
template<class T> bool ckmin(T& a, const T& b) { return b < a ? a = b, 1 : 0; }
template<class T> bool ckmax(T& a, const T& b) { return a < b ? a = b, 1 : 0; }
 
template<class T> void remDup(vector<T>& v) { sor(v); v.erase(unique(all(v)), v.end()); }
 
const int MOD = 1e9 + 7;
const int MX = 1e5 + 10;
const ll INF = 1e18;

int N, M; ll C[MX]; vpi adj[MX]; bool inCyc[MX]; int inDeg[MX]; ll ans[MX];

int main() {
    FASTIO;

    cin >> N >> M;

    if (M > N) {
        return cout << "0", 0;
    }
    FOR(i, 1, N + 1) {
        cin >> C[i];
    }
    FOR(i, 1, M + 1) {
        int A, B; cin >> A >> B;

        adj[A].pb({B, i});
        adj[B].pb({A, i});

        inDeg[A]++;
        inDeg[B]++;
    }
    FOR(i, 1, N + 1) inCyc[i] = true;

    queue<int> Q;

    FOR(i, 1, N + 1) {
        if (inDeg[i] == 1) {
            Q.push(i);
        }
    }
    while (!Q.empty()) {
        int cur = Q.front(); Q.pop();

        inCyc[cur] = false;

        EACH(Y, adj[cur]) {
            if (!inCyc[Y.f]) continue;

            ans[Y.s] = C[cur];

            inDeg[Y.f]--;
            C[Y.f] -= ans[Y.s];
            
            adj[Y.f].erase(find(all(adj[Y.f]), pi{cur, Y.s}));

            if (inDeg[Y.f] == 1) {
                Q.push(Y.f);
            }
        }
    }
   // cout << ans[11] << "HI " << "\n";
    if (M == N - 1) {
        FOR(i, 1, M + 1) {
            cout << 2 * ans[i] << "\n";
        }
        return 0;
    }
    vi cyc, edges; int curNode = -1;

    FOR(i, 1, N + 1) {
        if (inCyc[i]) {
            curNode = i; 
            edges.pb(adj[i][0].s);
            break;
        }
    }
    while (inCyc[curNode]) {
        inCyc[curNode] = false;

        cyc.pb(curNode);

        EACH(Y, adj[curNode]) {
            if (Y.s != edges.bk) {
                curNode = Y.f;
                edges.pb(Y.s);
                break;
            }
        }
    }
    edges.pop_back();
    
    N = sz(cyc);
    
    if (N % 2 == 0) {
        return cout << "0", 0;
    }
    ll sum = 0;
    
    EACH(i, cyc) {
        sum += C[i];
    }
    cout << sum << "\n";
    
    sum /= 2;
    
    vpi newCyc; int ind = 0;

    while (sz(newCyc) < N) {
        newCyc.pb({cyc[ind], ind});

        ind = (ind + 2) % N;
    }
    F0R(i, N) {
        newCyc.pb(newCyc[i]);
    }
    vl pref(sz(newCyc) + 1, 0);

    FOR(i, 1, sz(newCyc) + 1) {
        pref[i] = pref[i - 1] + C[newCyc[i - 1].f];
    }
    int numForward = (N - 1) / 2;

    F0R(i, N) {
        int curEdge = edges[(newCyc[i].s + N - 1) % N];
        
        ans[curEdge] = sum - (pref[i + numForward] - pref[i]);
    }
    FOR(i, 1, M + 1) {
        cout << 2 * ans[i] << "\n";
    }
}

• Subtask 1: 30 / 30
• Subtask 2: 44.074074074074076 / 70