Submission #1003800

#	Time	Username	Problem	Language	Result	Execution time	Memory
1003800		overwatch9	Robot (JOI21_ho_t4)	C++17	0 / 100	3059 ms	24764 KiB

Main

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int maxn = 1e5 + 1;
vector <array <int, 3>> adj[maxn];
bool processed[maxn][2];
ll dis[maxn][2];
int main() {
    int n, m;
    cin >> n >> m;
    for (int i = 0; i < m; i++) {
        int a, b, c, p;
        cin >> a >> b >> c >> p;
        adj[a].push_back({b, c, p});
        adj[b].push_back({a, c, p});
    }
    for (int i = 2; i <= n; i++)
        dis[i][0] = dis[i][1] = 1e18;
    priority_queue <array <ll, 4>> pq;
    pq.push({0, 0, 1, 0});
    ll ans = 1e18;
    while (!pq.empty()) {
        int s = pq.top()[2];
        int col = pq.top()[1];
        int p = pq.top()[3];
        bool changed = (col < 0);
        pq.pop();
        if (s == n)
            ans = min(ans, dis[s][changed]);
        if (processed[s][changed])
            continue;
        processed[s][changed] = true;
        vector <int> cnt(m+1);
        vector <ll> sum(m+1);
        for (auto i : adj[s]) {
            if (i[0] != p || (i[0] == p && !changed)) {
                cnt[i[1]]++;
                sum[i[1]] += i[2];
            }
        }
        // if (changed)
        //     cnt[-col]--;
        for (auto i : adj[s]) {
            int nxt = i[0], col2 = i[1];
            if (nxt == p)
                continue;
            ll cost = min((ll)i[2], sum[i[1]] - i[2]);
            // if ()
            if (cnt[col2] == 1) {
                if (dis[nxt][false] > dis[s][changed]) {
                    dis[nxt][false] = dis[s][changed];
                    pq.push({-dis[nxt][false], col2, nxt, s});
                }
            }
            bool x = true;
            if (cost == sum[i[1]] - i[2] && i[2] != sum[i[1]] - i[2])
                x = false;
            if (dis[nxt][x] > dis[s][changed] + cost) {
                dis[nxt][x] = dis[s][changed] + cost;
                if (x)
                    col2 = -col2;
                pq.push({-dis[nxt][x], col2, nxt, s});
            }
        }
    }
    if (ans == 1e18)
        ans = -1;
    cout << ans << '\n';
}

• Subtask 1: 0 / 34
• Subtask 2: 0 / 24
• Subtask 3: 0 / 42