Submission #736371

#	Time	Username	Problem	Language	Result	Execution time	Memory
736371		Cookie	Cat Exercise (JOI23_ho_t4)	C++14	100 / 100	339 ms	54548 KiB

Main

#include<bits/stdc++.h>
#include<fstream>
using namespace std;
ifstream fin("WINTER.inp");
ofstream fout("WINTER.out");
 
#define ll long long
#define pb push_back
#define forr(i, a, b) for(int i = a; i < b; i++)
#define dorr(i, a, b) for(int i = a; i >= b; i--)
#define ld long double
#define vt vector
#include<fstream>
#define fi first
#define se second
#define pll pair<ll, ll>
#define pii pair<int, int>
const ld PI = 3.14159265359;
const int x[4] = {1, -1, 0, 0};
const int y[4] = {0, 0, 1, -1};
const ll mod = 1e9 + 7;
const int mxn = 2e5, mxm = 1e5, sq = 400;
const int base = (1 << 18);
const ll inf = 1e9;
const ld pre = 1e-6;
int n;
int a[mxn + 1], dep[mxn + 1], up[mxn + 1][18], p[mxn + 1], to[mxn + 1];
ll dp[mxn + 1];
vt<int>adj[mxn + 1];
vt<pii>g[mxn + 1];
int lca(int u, int v){
    if(dep[u] < dep[v])swap(u, v);
    int k = dep[u] - dep[v];
    for(int i = 0; i < 18; i++){
        if(k & (1 << i)){
            u = up[u][i];
        }
    }
    if(u == v)return(u);
    for(int i = 17; i >= 0; i--){
        if(up[u][i] != up[v][i]){
            u = up[u][i]; v = up[v][i];
        }
    }
    return(up[u][0]);
}
void dfs2(int s){
    for(auto [i, w]: g[s]){
        dfs2(i);
        dp[s] = max(dp[s], dp[i] + w);
    }
}
void dfs(int s, int pre){
    for(auto i: adj[s]){
        if(i != pre){
            dep[i] = dep[s] + 1; up[i][0] = s;
            dfs(i, s);
        }
    }
}
int fp(int u){
    if(p[u] == u)return(u);
    return(p[u] = fp(p[u]));
}
void unon(int u, int v){
    u = fp(u); v = fp(v);
    if(u == v)return;
    if(a[u]  < a[v])swap(u, v);
    p[v] = u;
}
signed main(){
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin >> n;
    forr(i, 1, n + 1){
        cin >> a[i]; to[a[i]] = i;
    }
    forr(i, 1, n){
        int u, v; cin >> u >> v;
        adj[u].pb(v); adj[v].pb(u);
    }
    
    dfs(1, -1);
    forr(j, 1, 18){
        forr(i, 1, n + 1){
            up[i][j] = up[up[i][j - 1]][j - 1];
        }
    }
    forr(i, 1, n + 1)p[i] = i;
    for(int i = 1; i <= n; i++){
        int id = to[i];
        for(auto j: adj[id]){
            if(a[j] < a[id]){
                int id2 = fp(j);
                //cout << id << " " << id2 << " " << dep[id] + dep[id2] - 2 * dep[lca(id, id2)] << "\n";
                unon(id, id2); g[id].pb(make_pair(id2, dep[id] + dep[id2] - 2 * dep[lca(id, id2)]));
            }
        }
    }
    dfs2(to[n]);
    cout << dp[to[n]];
    return(0);
}

Compilation message (stderr)

Main.cpp: In function 'void dfs2(int)':
Main.cpp:48:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   48 |     for(auto [i, w]: g[s]){
      |              ^

• Subtask 1: 7 / 7
• Subtask 2: 7 / 7
• Subtask 3: 7 / 7
• Subtask 4: 10 / 10
• Subtask 5: 20 / 20
• Subtask 6: 23 / 23
• Subtask 7: 26 / 26