Submission #1216912

#	Time	Username	Problem	Language	Result	Execution time	Memory
1216912		InvMOD	Robot (JOI21_ho_t4)	C++20	100 / 100	706 ms	85628 KiB

Main

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

#define fi first
#define se second
#define gcd __gcd
#define sz(v) (int) v.size()
#define pb push_back
#define pi pair<int,int>
#define all(v) (v).begin(), (v).end()
#define compact(v) (v).erase(unique(all(v)), (v).end())
#define FOR(i, a, b) for(int i = (a); i <= (b); i++)
#define ROF(i, a, b) for(int i = (a); i >= (b); i--)
#define dbg(x) "[" #x " = " << (x) << "]"
#define int long long // forget to define int long long <(")

using ll = long long;
using ld = long double;
using ull = unsigned long long;

template<typename T> bool ckmx(T& a, const T& b){if(a < b) return a = b, true; return false;}
template<typename T> bool ckmn(T& a, const T& b){if(a > b) return a = b, true; return false;}

const int N = 2e5+5;
const ll MOD = 1e9+7;
const ll INF = 1e18;




void solve()
{
    int n,m; cin >> n >> m;

    vector<map<int, vector<pair<int,int>>>> adj(n + 1);

    vector<map<int,int>> total_cost(n + 1);
    FOR(i, 1, m){
        int u,v,C,P; cin >> u >> v >> C >> P;

        adj[u][C].emplace_back(v, P);
        adj[v][C].emplace_back(u, P);
        total_cost[u][C] += P;
        total_cost[v][C] += P;
    }

    vector<map<int, int>> dist(n + 1);

    const int Mx = m * 2;
    struct Node{
        int u,color,dist;
        Node(int u = 0, int color = 0, int dist = 0): u(u), color(color), dist(dist) {}

        bool operator < (const Node& q) const{
            return dist > q.dist;
        };
    };

    priority_queue<Node> pq;

    dist[1][Mx] = 0;
    pq.push(Node(1, Mx, 0));
    
    /*
      the only reason of changing only color of edge i is to reduce the cost of total - edge at the next v
    */

    while(!pq.empty()){
        Node eq = pq.top(); pq.pop();

        int x = eq.u, cur_color = eq.color;
        if(eq.dist > dist[x][cur_color]) continue;

        if(cur_color == Mx){
            for(auto [ncolor, Edge] : adj[x]){
                for(auto [v, cost] : Edge){
                    int total = total_cost[x][ncolor];

                    int ncost = dist[x][Mx] + min(total - cost, cost);
                    if(!dist[v].count(Mx) || ckmn(dist[v][Mx], ncost)){
                        dist[v][Mx] = ncost;
                        pq.push(Node(v, Mx, dist[v][Mx]));
                    }

                    if(!dist[v].count(ncolor) || ckmn(dist[v][ncolor], dist[x][Mx])){
                        dist[v][ncolor] = dist[x][Mx];
                        pq.push(Node(v, ncolor, dist[v][ncolor]));
                    }
                }
            }
        }
        else{
            int total = total_cost[x][cur_color];
            for(auto [v, cost] : adj[x][cur_color]){
                int ncost = dist[x][cur_color] + total - cost;

                if(!dist[v].count(Mx) || ckmn(dist[v][Mx], ncost)){
                    dist[v][Mx] = ncost;
                    pq.push(Node(v, Mx, dist[v][Mx]));
                }
            }
        }
    }

    cout << (dist[n].count(Mx) ? dist[n][Mx] : -1) << "\n";
}

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    #define name "InvMOD"
    if(fopen(name".INP", "r")){
        freopen(name".INP","r",stdin);
        freopen(name".OUT","w",stdout);
    }

    int t = 1; //cin >> t;
    while(t--) solve();
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:116:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  116 |         freopen(name".INP","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
Main.cpp:117:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  117 |         freopen(name".OUT","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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