제출 #973958

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
973958		GrindMachine	Islands (IOI08_islands)	C++17	100 / 100	491 ms	114416 KiB

islands

#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) (int)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
 
/*
 
 
 
*/
 
const int MOD = 1e9 + 7;
const int N = 1e6 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

vector<pii> adj[N];
vector<bool> on_cyc(N,1);
vector<ll> mxd(N);

void solve(int test_case)
{
    int n; cin >> n;
    vector<int> a(n+5), b(n+5);
    rep1(u,n){
        int v,w; cin >> v >> w;
        a[u] = v;
        b[u] = w;
        adj[v].pb({u,w});
    }
 
    queue<int> q;
    vector<int> indeg(n+5);
    rep1(i,n) indeg[a[i]]++;
    rep1(i,n){
        if(!indeg[i]){
            q.push(i);
        }
    }
 
    while(!q.empty()){
        int u = q.front();
        q.pop();
        on_cyc[u] = 0;
        int v = a[u];
        indeg[v]--;
        if(!indeg[v]){
            q.push(v);
        }
    }
 
    vector<bool> vis(n+5);
    vector<pii> nodes;
    vector<int> weights;
    vector<ll> p(n+5);
    ll ans = 0;
 
    rep1(i,n){
        if(!on_cyc[i]) conts;
        if(vis[i]) conts;
        
        nodes.clear();
        weights.clear();
        nodes.shrink_to_fit();
        weights.shrink_to_fit();
 
        int j = i;
        while(!vis[j]){
            vis[j] = 1;
            nodes.pb({j,-1});
            weights.pb(b[j]);
            j = a[j];
        }
 
        int siz = sz(nodes);
        rep(j,siz){
            nodes[j].ss = weights[(j-1+siz)%siz];
        }
 
        rep(j,siz){
            p[j] = nodes[j].ss;
            if(j) p[j] += p[j-1]; 
        }
 
        ll len = p[siz-1];
        ll best = 0, mx1 = -inf2, mx2 = -inf2;
    
        vector<int> ord;

        rep(j,siz){
            int u = nodes[j].ff;
            ord.clear();

            {
                q.push(u);
                while(!q.empty()){
                    int u = q.front();
                    q.pop();

                    ord.pb(u);
                    
                    for(auto [v,w] : adj[u]){
                        if(on_cyc[v]) conts;
                        q.push(v);
                    }
                }   
            }

            reverse(all(ord));

            ll diam = 0;

            {
                trav(u,ord){
                    pll tm = {0,0};
                    for(auto [v,w] : adj[u]){
                        if(on_cyc[v]) conts;
                        ll val = mxd[v]+w;
                        amax(mxd[u],val);
                        if(val > tm.ff){
                            tm.ss = tm.ff;
                            tm.ff = val;
                        }
                        else{
                            amax(tm.ss,val);
                        }
                    }
                 
                    amax(diam,tm.ff+tm.ss);
                    amax(diam,mxd[u]);
                }
            }

            ll d = mxd[u];
            amax(best,d+p[j]+mx1);
            amax(best,d-p[j]+mx2+len);
            amax(mx1,d-p[j]);
            amax(mx2,d+p[j]);
            amax(best,diam);
        }
 
        ans += best;
    }
 
    cout << ans << endl;
}
 
int main()
{
    fastio;
 
    int t = 1;
    // cin >> t;
 
    rep1(i, t) {
        solve(i);
    }
 
    return 0;
}

• Subtask 1: 33 / 33
• Subtask 2: 3 / 3
• Subtask 3: 4 / 4
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10