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Submission #510128

# Submission time Handle Problem Language Result Execution time Memory
510128 2022-01-14T17:59:30 Z Yazan_Alattar Islands (IOI08_islands) C++14
0 / 100
 476 ms 131076 KB 
#include <iostream>
#include <fstream>
#include <vector>
#include <cstring>
#include <algorithm>
#include <set>
#include <map>
#include <queue>
#include <list>
#include <utility>
#include <cmath>
#include <numeric>
#include <assert.h>
using namespace std;
typedef long long ll;
#define F first
#define S second
#define pb push_back
#define endl "\n"
#define all(x) x.begin(), x.end()
const int M = 200007;
const ll inf = 1e18;
const ll mod = 1e9 + 7;
const double pi = acos(-1);
const int dx[] = {1, 0, -1, 0}, dy[] = {0, 1, 0, -1};

vector < pair < ll, pair <int,int> > > edges;
vector < pair <int,ll> > adj[M];
vector <int> nodes;
pair <int,int> edge;
ll n, cost[M], mxchild[M], p[M], ans;
bool vist[M];

void get(int node)
{
    nodes.pb(node);
    vist[node] = 1;
    for(auto i : adj[node]){
        edges.pb({i.S, {node, i.F}});
        if(!vist[i.F]) get(i.F);
    }
    return;
}

void dfs(int node, ll cur)
{
//    cout << node << " " << edge.F << " " << edge.S << endl;
    cost[node] = cur;
    mxchild[node] = cur;
    for(auto i : adj[node]){
        if(i.F == p[node] || edge == make_pair(node, i.F) || edge == make_pair(i.F, node)) continue;
        p[i.F] = node;
        dfs(i.F, cur + i.S);
        mxchild[node] = max(mxchild[node], mxchild[i.F]);
    }
    return;
}

pair <int,int> calc(int node)
{
    pair <ll,ll> ret;
    int cur = node;
    while(p[cur] != 1) cur = p[cur];
    ret.F = cost[node] - cost[cur];
    ret.S = mxchild[node];
}

ll best(int node)
{
    ll ret = 0;
    for(auto i : adj[node]){
        if(i.F == p[node]) continue;
        if(i.F == edge.F || i.F == edge.S) return -1;
        ll x = best(i.F);
        if(x == -1 && node != 1) return -1;
        else ret = max(ret, best(i.F));
    }
    return ret;
}

int main()
{
//    ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    cin >> n;
    for(int i = 1; i <= n; ++i){
        ll x, y;
        cin >> x >> y;
        adj[x].pb({i, y});
        adj[i].pb({x, y});
    }
    for(int j = 1; j <= n; ++j){
        if(vist[j]) continue;
        get(j);
        sort(all(edges), greater < pair < ll, pair <int,int> > > ());
        edge = {edges.back().S.F, edges.back().S.S};
        int root = 0;
        for(auto i : nodes) if(i != edge.F && i != edge.S) {root = i; break;}
        if(root == 0){
//            for(auto i : edges) cout << i.S.F << " " << i.S.S << " " << i.F << endl;
            ans += edges[0].F;
            continue;
        }
        dfs(root, 0);
        ll mx1 = 0, mx2 = 0, mx = 0;
        for(auto i : nodes){
            if(cost[i] > mx1) mx2 = mx1, mx1 = cost[i];
            else if(cost[i] > mx2) mx2 = cost[i];
        }
        mx = mx1 + mx2;
        mx1 = best(root);
        pair <ll,ll> nodea = calc(edge.F);
        pair <ll,ll> nodeb = calc(edge.S);
        mx = max(mx, nodea.F + nodeb.S + edges.back().F);
        mx = max(mx, nodea.F + nodeb.F + edges.back().F);
        mx = max(mx, nodea.S + nodeb.F + edges.back().F);
        mx = max(mx, nodea.S + nodeb.S + edges.back().F);
        mx = max(mx, mx1 + cost[edge.F] + nodeb.S + edges.back().F);
        mx = max(mx, mx1 + cost[edge.F] + nodeb.F + edges.back().F);
        mx = max(mx, mx1 + nodea.F + cost[edge.S] + edges.back().F);
        mx = max(mx, mx1 + nodea.S + cost[edge.S] + edges.back().F);
        ans += mx;
        edges.clear();
        nodes.clear();
    }
    cout << ans << endl;
    return 0;
}

Compilation message

islands.cpp: In function 'std::pair<int, int> calc(int)':
islands.cpp:66:1: warning: no return statement in function returning non-void [-Wreturn-type]
   66 | }
      | ^

Subtask #1
0 / 33.0

# Verdict Execution time Memory Grader output
1 Runtime error 8 ms 10060 KB Execution killed with signal 11
2 Runtime error 8 ms 10060 KB Execution killed with signal 11
3 Runtime error 10 ms 10276 KB Execution killed with signal 11
4 Runtime error 9 ms 10060 KB Execution killed with signal 11
5 Runtime error 65 ms 131076 KB Execution killed with signal 9
6 Runtime error 8 ms 10060 KB Execution killed with signal 11
7 Runtime error 9 ms 10076 KB Execution killed with signal 11
8 Runtime error 8 ms 10060 KB Execution killed with signal 11
9 Runtime error 9 ms 10060 KB Execution killed with signal 11
10 Runtime error 10 ms 10068 KB Execution killed with signal 11
11 Runtime error 12 ms 10128 KB Execution killed with signal 11

Subtask #2
0 / 3.0

# Verdict Execution time Memory Grader output
1 Runtime error 9 ms 10444 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -

Subtask #3
0 / 4.0

# Verdict Execution time Memory Grader output
1 Runtime error 66 ms 131076 KB Execution killed with signal 9
2 Halted 0 ms 0 KB -

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 279 ms 131076 KB Execution killed with signal 9
2 Halted 0 ms 0 KB -

Subtask #5
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 67 ms 25580 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -

Subtask #6
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 476 ms 131076 KB Execution killed with signal 9
2 Halted 0 ms 0 KB -

Subtask #7
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 135 ms 29860 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 6 ms 9932 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -

Subtask #9
0 / 10.0

# Verdict Execution time Memory Grader output
1 Runtime error 20 ms 11924 KB Execution killed with signal 11
2 Halted 0 ms 0 KB -