Submission #1112020

#	Time	Username	Problem	Language	Result	Execution time	Memory
1112020		_callmelucian	Robot (JOI21_ho_t4)	C++14	0 / 100	3081 ms	104984 KiB

Main

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

typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> pl;
typedef pair<int,int> pii;
typedef tuple<ll,int,int,int> tpl;

#define all(a) a.begin(), a.end()
#define filter(a) a.erase(unique(all(a)), a.end())

const int mn = 2e5 + 5;
vector<ll> dist[2][mn], cmpID[mn];
map<int,ll> sumWeight[mn];
vector<bool> vis[2][mn];
ll color[mn], weight[mn];
vector<pii> adj[mn];

int getArc (int u, int targ) {
    return lower_bound(all(cmpID[u]), targ) - cmpID[u].begin();
}

int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);

    int n, m; cin >> n >> m;
    for (int i = 1; i <= m; i++) {
        int a, b; cin >> a >> b >> color[i] >> weight[i];
        cmpID[a].push_back(i), cmpID[b].push_back(i);
        adj[a].emplace_back(b, i);
        adj[b].emplace_back(a, i);
    }

    for (int i = 1; i <= n; i++) {
        sort(all(cmpID[i]));
        for (int j = 0; j < 2; j++) {
            dist[j][i] = vector<ll>(cmpID[i].size(), LLONG_MAX);
            vis[j][i] = vector<bool>(cmpID[i].size());
        }

        for (pii item : adj[i]) {
            int j, idx; tie(j, idx) = item;
            sumWeight[i][color[idx]] += weight[idx];
        }
    }

    priority_queue<tpl> pq;
    pq.emplace(0, 1, 1, 0), dist[1][1][0] = 0;

    while (pq.size()) {
        ll dst; int keepColor, u, arc;
        tie(dst, keepColor, u, arc) = pq.top(); pq.pop();
        if (vis[keepColor][u][arc]) continue;
        vis[keepColor][u][arc] = 1;

        int eID = cmpID[u][arc], preColor = (u == 1 ? -1 : color[eID]);
        for (pii item : adj[u]) {
            int v, idx; tie(v, idx) = item;
            int nxtArc = getArc(v, idx);

            assert(cmpID[v][nxtArc] == idx);

            if (color[idx] != preColor || !keepColor) {
                // use color[idx] as the current color
                ll curW = sumWeight[u][color[idx]] - weight[idx];
                if (preColor == color[idx]) curW -= weight[eID];

                if (dist[keepColor][u][arc] + curW < dist[1][v][nxtArc]) {
                    dist[1][v][nxtArc] = dist[keepColor][u][arc] + curW;
                    pq.emplace(-dist[1][v][nxtArc], 1, v, nxtArc);
                }
            }
            if (1) {
                // use a new color
                if (dist[keepColor][u][arc] + weight[idx] < dist[0][v][nxtArc]) {
                    dist[0][v][nxtArc] = dist[keepColor][u][arc] + weight[idx];
                    pq.emplace(-dist[0][v][nxtArc], 0, v, nxtArc);
                }
            }
        }
    }

    ll ans = LLONG_MAX;
    for (int j = 0; j < 2; j++)
        for (int i = 0; i < cmpID[n].size(); i++) ans = min(ans, dist[j][n][i]);
    cout << (ans == LLONG_MAX ? -1 : ans);

    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:88:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   88 |         for (int i = 0; i < cmpID[n].size(); i++) ans = min(ans, dist[j][n][i]);
      |                         ~~^~~~~~~~~~~~~~~~~

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