Submission #544929

#	Time	Username	Problem	Language	Result	Execution time	Memory
544929		SmolBrain	Dreaming (IOI13_dreaming)	C++17	10 / 100	1084 ms	12864 KiB

dreaming

// Om Namah Shivaya
// GM in 121 days

#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 <class 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 endl '\n'
#define pb push_back
#define conts continue
#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 ff first
#define ss second
#define ceil2(x,y) ((x+y-1) / (y))
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#ifndef ONLINE_JUDGE
#define debug(x) cout << #x <<" = "; print(x); cout << endl
#else
#define debug(x)
#endif

#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)

bool iseven(ll n) {if ((n & 1) == 0) return true; return false;}

void print(ll t) {cout << t;}
void print(int t) {cout << t;}
void print(string t) {cout << t;}
void print(char t) {cout << t;}
void print(double t) {cout << t;}
void print(ld t) {cout << t;}

template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(pair <T, V> p) {cout << "{"; print(p.ff); cout << ","; print(p.ss); cout << "}";}
template <class T> void print(vector <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T> void print(set <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T> void print(multiset <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T, class V> void print(map <T, V> v) {cout << "[ "; for (auto i : v) {print(i); cout << " ";} cout << "]";}
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); }

void usaco(string filename) {
    freopen((filename + ".in").c_str(), "r", stdin);
    freopen((filename + ".out").c_str(), "w", stdout);
}

const int MOD = 1e9 + 7;
const int maxn = 1e5 + 5;
const int inf1 = 1e9 + 5;
const ll inf2 = ll(1e18) + 5;

#include "dreaming.h"

vector<pii> adj[maxn];
vector<int> mxsum(maxn);
vector<bool> vis(maxn);
int mn = inf1, best = -1;
int mxval = -1, mxnode = -1;

void dfs1(int node, int par, int sum, int root) {
    amax(mxsum[root], sum);

    for (auto [child, w] : adj[node]) {
        if (child == par) conts;
        dfs1(child, node, sum + w, root);
    }
}

void dfs2(int node, int par) {
    if (mxsum[node] < mn) {
        mn = mxsum[node];
        best = node;
    }

    vis[node] = 1;

    for (auto [child, w] : adj[node]) {
        if (child == par) conts;
        dfs2(child, node);
    }
}

void dfs3(int node, int par, int sum) {
    if (sum > mxval) {
        mxval = sum;
        mxnode = node;
    }

    for (auto [child, w] : adj[node]) {
        if (child == par) conts;
        dfs3(child, node, sum + w);
    }
}

int travelTime(int n, int m, int l, int a[], int b[], int t[]) {
    rep(i, m) {
        int u = a[i], v = b[i], w = t[i];
        adj[u].pb({v, w});
        adj[v].pb({u, w});
    }

    rep(i, n) {
        dfs1(i, -1, 0, i);
    }

    vector<int> vals;

    rep(i, n) {
        if (vis[i]) conts;
        mn = inf1, best = -1;
        dfs2(i, -1);
        vals.pb(best);
    }

    int siz = sz(vals);

    rep1(i, siz - 1) {
        int u = vals[0], v = vals[i];
        adj[u].pb({v, l}), adj[v].pb({u, l});

        int x = mxsum[u], y = mxsum[v];

        amax(mxsum[u], y + l);
        amax(mxsum[v], x + l);

        if (mxsum[v] < mxsum[u]) {
            vals[0] = v;
        }
    }

    dfs3(0, -1, 0);
    dfs3(mxnode, -1, 0);

    return mxval;
}

Compilation message (stderr)

dreaming.cpp: In function 'void usaco(std::string)':
dreaming.cpp:64:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |     freopen((filename + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
dreaming.cpp:65:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |     freopen((filename + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 14
• Subtask 2: 10 / 10
• Subtask 3: 0 / 23
• Subtask 4: 0 / 18
• Subtask 5: 0 / 12
• Subtask 6: 0 / 23