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Submission #958317

# Submission time Handle Problem Language Result Execution time Memory
958317 2024-04-05T11:50:20 Z amine_aroua Valley (BOI19_valley) C++17
100 / 100
 208 ms 53844 KB 
#include <bits/stdc++.h>
//#pragma GCC optimize("O3")
//#pragma GCC optimize("unroll-loops")
using namespace std;
#define int long long
#define vi vector<int>
#define vl vector<long long>
#define vii vector<pair<int,int>>
#define vll vector<pair<long long,long long>>
#define pb push_back
#define ll long long
#define ld long double
#define nl '\n'
#define boost ios::sync_with_stdio(false)
#define mp make_pair
#define se second
#define fi first
#define fore(i, y) for(int i = 0; i < y; i++)
#define forr(i,x,y) for(int i = x;i<=y;i++)
#define forn(i,y,x) for(int i = y; i >= x; i--)
#define all(v) v.begin(),v.end()
#define sz(v) (int)v.size()
#define clr(v,k) memset(v,k,sizeof(v))
#define rall(v) v.rbegin() , v.rend()
#define pii pair<int,int>
#define pll pair<ll , ll>

const ll MOD = 1e9 + 7;
const ll INF = 1e18 + 1;

ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a ;} // greatest common divisor (gcd)
ll lcm(ll a , ll b) {return a * (b / gcd(a , b));} // least common multiple (lcm)

// HERE IS THE SOLUTION
const int N = 1e5 + 10;
const int LOG = 20;
int n , s , q, e;
vii adj[N];
int mn[LOG][N] , par[LOG][N];
pii edges[N];
int depth[N];
int cost_closest[N];
int distE[N];
int Time = -1;
int tin[N] , tout[N];
void pre_dfs(int x , int p)
{
    Time++;
    tin[x] = Time;
    for(auto [u , c] : adj[x])
    {
        if(u == p)
            continue;
        depth[u] = depth[x] + 1;
        distE[u] = distE[x] + c;
        pre_dfs(u , x);
        cost_closest[x] = min(cost_closest[u] + c , cost_closest[x]);
    }
    tout[x] = Time;
}

void main_dfs(int x , int p)
{
    for(auto [u , c] : adj[x])
    {
        if(u == p)
            continue;
        mn[0][u] = cost_closest[x] - distE[x];
        par[0][u] = x;
        forr(j , 1 , LOG - 1)
        {
            par[j][u] = par[j - 1][par[j - 1][u]];
            mn[j][u] = min(mn[j - 1][u] , mn[j - 1][par[j - 1][u]]);
        }
        main_dfs(u , x);
    }
}

bool is_ancestor(int anc , int node)
{
    return (tin[node] <= tout[anc] && tin[node] >= tin[anc]);
}

signed main()
{
    boost;
    cin.tie(0);
    cout.tie(0);
    cin>>n>>s>>q>>e;
    e--;
    forr(i ,1, n - 1)
    {
        int u , v , c;
        cin>>u>>v>>c;
        u-- , v--;
        adj[u].pb({v , c});
        adj[v].pb({u , c});
        edges[i] = { u , v};
    }
    fore(i , n)
        cost_closest[i] = INF;
    fore(i , s)
    {
        int x;
        cin>>x;
        x--;
        cost_closest[x] = 0;
    }
    distE[e] = 0;
    depth[e] = 0;
    pre_dfs(e , -1);
    fore(i , LOG)
    {
        fore(j , n)
        {
            mn[i][j] = INF;
            par[i][j] = e;
        }
    }
    main_dfs(e , -1);
    while(q--)
    {
        int i , u;
        cin>>i>>u;
        u--;
        int p = edges[i].first;
        if(depth[edges[i].second] > depth[p])
            p = edges[i].second;
        if(is_ancestor(p , u))
        {
            if(cost_closest[p] >= INF)
            {
                cout<<"oo"<<nl;
                continue;
            }
            int ans = cost_closest[u] - distE[u];
            int node = u;
            forn(j , LOG - 1 , 0)
            {
                int new_node = par[j][node];
                if(is_ancestor(p , new_node))
                {
                    ans = min(ans , mn[j][node]);
                    node = new_node;
                }
            }
            ans+=distE[u];
            cout<<ans<<nl;
        }
        else
        {
            cout<<"escaped"<<nl;
        }
    }
}

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 39516 KB Output is correct
2 Correct 9 ms 39424 KB Output is correct
3 Correct 7 ms 39516 KB Output is correct
4 Correct 7 ms 39436 KB Output is correct

Subtask #2
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 39516 KB Output is correct
2 Correct 9 ms 39424 KB Output is correct
3 Correct 7 ms 39516 KB Output is correct
4 Correct 7 ms 39436 KB Output is correct
5 Correct 6 ms 39372 KB Output is correct
6 Correct 7 ms 39516 KB Output is correct
7 Correct 6 ms 39512 KB Output is correct
8 Correct 10 ms 39512 KB Output is correct
9 Correct 8 ms 39516 KB Output is correct
10 Correct 8 ms 39516 KB Output is correct
11 Correct 6 ms 39512 KB Output is correct
12 Correct 6 ms 39516 KB Output is correct
13 Correct 7 ms 39516 KB Output is correct
14 Correct 6 ms 39488 KB Output is correct

Subtask #3
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 151 ms 47252 KB Output is correct
2 Correct 175 ms 48976 KB Output is correct
3 Correct 167 ms 49080 KB Output is correct
4 Correct 186 ms 51048 KB Output is correct
5 Correct 167 ms 51144 KB Output is correct
6 Correct 198 ms 53332 KB Output is correct

Subtask #4
41.0 / 41.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 39516 KB Output is correct
2 Correct 9 ms 39424 KB Output is correct
3 Correct 7 ms 39516 KB Output is correct
4 Correct 7 ms 39436 KB Output is correct
5 Correct 6 ms 39372 KB Output is correct
6 Correct 7 ms 39516 KB Output is correct
7 Correct 6 ms 39512 KB Output is correct
8 Correct 10 ms 39512 KB Output is correct
9 Correct 8 ms 39516 KB Output is correct
10 Correct 8 ms 39516 KB Output is correct
11 Correct 6 ms 39512 KB Output is correct
12 Correct 6 ms 39516 KB Output is correct
13 Correct 7 ms 39516 KB Output is correct
14 Correct 6 ms 39488 KB Output is correct
15 Correct 151 ms 47252 KB Output is correct
16 Correct 175 ms 48976 KB Output is correct
17 Correct 167 ms 49080 KB Output is correct
18 Correct 186 ms 51048 KB Output is correct
19 Correct 167 ms 51144 KB Output is correct
20 Correct 198 ms 53332 KB Output is correct
21 Correct 121 ms 48700 KB Output is correct
22 Correct 132 ms 48484 KB Output is correct
23 Correct 136 ms 48724 KB Output is correct
24 Correct 170 ms 50776 KB Output is correct
25 Correct 185 ms 53844 KB Output is correct
26 Correct 120 ms 48468 KB Output is correct
27 Correct 123 ms 48468 KB Output is correct
28 Correct 130 ms 48724 KB Output is correct
29 Correct 170 ms 50096 KB Output is correct
30 Correct 195 ms 51796 KB Output is correct
31 Correct 117 ms 48724 KB Output is correct
32 Correct 128 ms 48656 KB Output is correct
33 Correct 150 ms 48980 KB Output is correct
34 Correct 208 ms 50764 KB Output is correct
35 Correct 187 ms 53536 KB Output is correct
36 Correct 179 ms 50552 KB Output is correct