Submission #772889

#	Time	Username	Problem	Language	Result	Execution time	Memory
772889		YassineBenYounes	Valley (BOI19_valley)	C++17	36 / 100	141 ms	27436 KiB

valley

#include<bits/stdc++.h>
typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;
typedef double db;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define pbds tree<pair<ll, ll>, null_type, less<pair<ll,ll>>,rb_tree_tag, tree_order_statistics_node_update>
using namespace __gnu_pbds;
ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a ;} // greatest common divisor (PGCD)
ll lcm(ll a , ll b) {return (a * b) / gcd(a , b);} // least common multiple (PPCM)
int dx[8] = {1, 0, 0, -1, 1, 1, -1, -1};
int dy[8] = {0, 1, -1, 0, 1, -1, -1, 1};
#define endl "\n"
#define ss second
#define ff first
#define all(x) (x).begin() , (x).end()
#define pb push_back
#define vi vector<int>
#define vii vector<pair<int,int>>
#define vl vector<ll>
#define vll vector<pair<ll,ll>>
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pdd  pair<double,double>
#define vdd  vector<pdd>
#define speed ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
using namespace std;
////////////////////Only Clear Code//////////////////////////

void usaco_problem(){
    freopen("milkvisits.in", "r", stdin);
    freopen("milkvisits.out", "w", stdout);
}

void init(){
    #ifndef ONLINE_JUDGE
 
freopen("input.txt", "r", stdin);
 
freopen("output.txt", "w", stdout);
 
#endif // ONLINE_JUDGE
}

const int mx = 2e5+5;
const int LOG = 25;
const ll inf = 1e18;
const ll mod = 1e8;

vi edges[mx];
bool shop[mx];
int n, s, q, e;
vector<vi> graph[mx];
int tin[mx], tout[mx];
ll res[mx];


int c = 0;
void solve(int node, int p){
    tin[node] = c++;
    tout[node] = 1;
    for(vi adj : graph[node]){
        if(adj[0] == p)continue;
        solve(adj[0], node);
        tout[node] += tout[adj[0]];
    }
}
ll ans;
void dfs(int node, int p, ll w, int no){
    if(shop[node]){
        if(ans == -1){
            ans = w;
        }
        else{
            ans = min(ans, w);
        }
    }
    for(vi adj : graph[node]){
        if(adj[0] == p || adj[2] == no)continue;
        dfs(adj[0], node, w + adj[1], no);
    }    
}

void run_case(){
    cin >> n >> s >> q >> e;
    for(int i = 1; i < n;i++){
        int a, b, c;cin >> a >> b >> c;
        edges[i] = {a, b, c};
        graph[a].pb({b, c, i});
        graph[b].pb({a, c, i});
    }
    for(int i = 0; i < s;i++){
        int a;cin >> a;
        shop[a] = 1;
    }
    solve(1, 1);
    for(int i = 1; i <= n;i++){
        tout[i] += tin[i]-1;
    }
    for(int i = 0; i < q;i++){
        int ind, node;cin >> ind >> node;
        int a = edges[ind][0], b = edges[ind][1];
        if(tin[a] > tin[b])swap(a, b);
        bool in_e = tin[e] >= tin[b] && tout[e] <= tout[b];
        bool in_node = tin[node] >= tin[b] && tout[node] <= tout[b];
        if(in_e == in_node){
            cout << "escaped" << endl;
            continue;
        }
        if(((ll)n*q) <= 1e6){
            ans = -1;
            dfs(node, node, 0, ind);
            if(ans == -1){
                cout << "oo" << endl;
            }
            else{
                cout << ans << endl;
            }
        }
        else{
            ll k = inf;
            for(vi adj : graph[node]){
                if((node == a && adj[0] == b) || (node == b && adj[0] == a))continue;
                k = min(k, (ll)adj[1]);
            }
            if(k == inf)cout << "oo" << endl;
            else cout << k << endl;
        }
    }
}

int main(){
    speed;
    int t;
    //cin >> t;
    t = 1;
    while(t--){
        run_case();
    }
}

/*
    NEVER GIVE UP!
    DOING SMTHNG IS BETTER THAN DOING NTHNG!!!
    Your Guide when stuck:
    - Continue keyword only after reading the whole input
    - Don't use memset with testcases
    - Check for corner cases(n=1, n=0)
    - Check where you declare n(Be careful of declaring it globally and in main)
*/

Compilation message (stderr)

valley.cpp: In function 'void usaco_problem()':
valley.cpp:32:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   32 |     freopen("milkvisits.in", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
valley.cpp:33:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |     freopen("milkvisits.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
valley.cpp: In function 'void init()':
valley.cpp:39:8: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   39 | freopen("input.txt", "r", stdin);
      | ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
valley.cpp:41:8: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 | freopen("output.txt", "w", stdout);
      | ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 27 / 27
• Subtask 3: 0 / 23
• Subtask 4: 0 / 41