Submission #758904

#	Time	Username	Problem	Language	Result	Execution time	Memory
758904		GrindMachine	Robot (JOI21_ho_t4)	C++17	0 / 100	382 ms	50836 KiB

Main

// Om Namah Shivaya

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x, y) ((x + y - 1) / (y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i, n) for(int i = 0; i < n; ++i)
#define rep1(i, n) for(int i = 1; i <= n; ++i)
#define rev(i, s, e) for(int i = s; i >= e; --i)
#define trav(i, a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a, b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a, b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*

refs:
https://usaco.guide/problems/joi-2021robot/solution

*/

const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

vector<array<ll,4>> adj[N];
map<ll,ll> adj_sum[N];

void solve(int test_case)
{
    ll n,m; cin >> n >> m;
    vector<array<ll,4>> edges(m+5);

    rep1(i,m){
        ll u,v,c,w; cin >> u >> v >> c >> w;
        edges[i] = {u,v,c,w};
        adj[u].pb({v,c,w,i});
        adj[v].pb({u,c,w,i});
        adj_sum[u][c] += w;
        adj_sum[v][c] += w;
    }

    priority_queue<array<ll,3>,vector<array<ll,3>>,greater<array<ll,3>>> pq;
    pq.push({0,1,-1});
    set<pll> st;

    while(!pq.empty()){
        auto [cost,u,prev_id] = pq.top();
        pq.pop();

        if(st.count({u,prev_id})) conts;
        st.insert({u,prev_id});

        if(u == n){
            cout << cost << endl;
            return;
        }

        for(auto [v,c,w,id] : adj[u]){
            // recolor edge and put ?
            pq.push({cost+w,v,-1});

            // recolor all adj guys
            ll add = adj_sum[u][c];
            add -= w;
        
            if(prev_id != -1){
                auto [u2,v2,c2,w2] = edges[prev_id];
                if(c == c2){
                    add -= w2;
                }
            }

            pq.push({cost+add,v,id});
        }
    }

    cout << -1 << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

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