Submission #446843

#	Time	Username	Problem	Language	Result	Execution time	Memory
446843		gsc2001	Robot (JOI21_ho_t4)	C++17	100 / 100	1126 ms	87676 KiB

Main

#include <bits/stdc++.h>

using namespace std;
#define ll long long
#define ld long double
#define f(i, l, r) for (int i = l; i <= r; i++)
#define debug(x) cout << #x << '=' << (x) << endl
#define pb push_back
#define all(x) x.begin(), x.end()
#define sz(x) (ll)(x).size()
#define ff first
#define ss second

using PLL = pair<ll, ll>;
using VL = vector<ll>;
using VLL = vector<pair<ll, ll>>;

// -------------------------------------------------------------------------------
constexpr int mod = 1e9 + 7;

void setIO(const string &name = "") {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    if (sz(name)) {
        freopen((name + ".in").c_str(), "r", stdin);
        freopen((name + ".out").c_str(), "w", stdout);
    }
}
// -------------------------------------------------------------------------------
// ------------------------Template End ------------------------------------------
// -------------------------------------------------------------------------------

struct Edge {
    ll color, changePrice, to;

    Edge(ll t, ll c, ll p) : color(c), changePrice(p), to(t) {

    }
};

constexpr ll inf = 1e18;

int main() {
    setIO();
    ll n, m;
    cin >> n >> m;
    vector<map<ll, vector<Edge>>> adj(n);
    vector<map<ll, ll>> colorCount(n);
    ll a, b, c, p;
    for (int i = 0; i < m; i++) {
        cin >> a >> b >> c >> p;
        a--, b--;
        adj[a][c].push_back(Edge(b, c, p));
        adj[b][c].push_back(Edge(a, c, p));
        colorCount[a][c] += p;
        colorCount[b][c] += p;
    }

    priority_queue<tuple<ll, ll, ll>> pq;
    vector<ll> dp(n, inf);
    vector<map<ll, ll>> dp2(n);
    dp[0] = 0;
    pq.push({0, 0, 0});

    ll distNow, node;
    while (!pq.empty()) {
        tie(distNow, node, c) = pq.top();
        pq.pop();
        distNow = -distNow;
        ll newDist;
        if (c) {
            if (dp2[node][c] != distNow) continue;
            for (auto edge: adj[node][c]) {
                // I can't change this one
                newDist = dp2[node][c] + colorCount[node][c] - edge.changePrice;
                if (newDist < dp[edge.to]) {
                    dp[edge.to] = newDist;
                    pq.push({-dp[edge.to], edge.to, 0});
                }

            }
        } else {
            if (dp[node] != distNow) continue;

            for (auto &edges: adj[node]) {
                for (auto edge : edges.second) {
                    // dont change this, change others
                    newDist = dp[node] + colorCount[node][edge.color] - edge.changePrice;
                    if (newDist < dp[edge.to]) {
                        dp[edge.to] = newDist;
                        pq.push({-dp[edge.to], edge.to, 0});
                    }

                    // change this one
                    newDist = dp[node] + edge.changePrice;
                    if (newDist < dp[edge.to]) {
                        dp[edge.to] = newDist;
                        pq.push({-dp[edge.to], edge.to, 0});
                    }

                    // change this one and others for ahead one
                    newDist = dp[node];
                    if (!dp2[edge.to].count(edge.color) || newDist < dp2[edge.to][edge.color]) {
                        dp2[edge.to][edge.color] = newDist;
                        pq.push({-dp2[edge.to][edge.color], edge.to, edge.color});
                    }

                }
            }
        }

    }

    cout << (dp[n - 1] >= inf ? -1 : dp[n - 1]);


    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'void setIO(const string&)':
Main.cpp:25:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   25 |         freopen((name + ".in").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:26:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   26 |         freopen((name + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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