Submission #1272408

#	Time	Username	Problem	Language	Result	Execution time	Memory
1272408		SirLemonMeringue	Airplane (NOI23_airplane)	C++20	0 / 100	190 ms	58864 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define MAX_N 200010
#define INF 200000000000000

int a[MAX_N];
vector<int> adj[MAX_N];

unordered_map<int,int> dist[MAX_N];
int highestSeen[MAX_N];

struct P {
    int dest, dist, height;
    bool operator< (P other) const {
        return dist > other.dist;
    }
};

signed main(){
    int n,m; cin >> n >> m;
    for(int i=1;i<=n;i++) cin >> a[i];
    for(int i=0;i<m;i++){
        int u,v; cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    fill(highestSeen,highestSeen+n+5,-1);
    priority_queue<P> todo;
    todo.push({1,0,0});
    while(!todo.empty()){
        P u = todo.top(); todo.pop();
        if (u.height > highestSeen[u.dest]){
            highestSeen[u.dest] = u.height;
            dist[u.dest][u.height] = u.dist;
            if (u.dest==n) continue;
            for(auto v : adj[u.dest]){
                // do not change height if legal
                if (u.height >= a[v]) todo.push({v,u.dist+1,u.height});
                // drop height if legal
                if (u.height-1 >= a[v]) todo.push({v,u.dist+1,u.height-1});
                // raise height to at least a[v]-1, then increase
                int lift = max((int)1, a[v]-u.height);
                todo.push({v, u.dist+lift,u.height+lift-1});
            }
        }
    }
    int res = INF;
    for(auto [a,b] : dist[n]){
        res = min(res, a+b);
    }
    cout << res << '\n';

    return 0;
}

• Subtask 1: 0 / 22
• Subtask 2: 0 / 10
• Subtask 3: 0 / 31
• Subtask 4: 0 / 37