Submission #1050006

#	Time	Username	Problem	Language	Result	Execution time	Memory
1050006		otarius	Race (IOI11_race)	C++17	100 / 100	269 ms	111696 KiB

race

#include <bits/stdc++.h>
#include <bits/extc++.h>
using namespace __gnu_pbds;
using namespace std;

#pragma GCC optimize("Ofast")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#define ff first
#define sc second
#define pb push_back
#define ll long long
#define pll pair<ll, ll>
#define pii pair<int, int>
#define ull unsigned long long
#define all(x) (x).begin(),(x).end()

// #define int long long
// #define int unsigned long long

// #define ordered_set(T) tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>
// #define ordered_multiset(T) tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update>

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

// const ll mod = 1e9 + 7;
// const ll mod = 998244353;

const ll inf = 1e9;
const ll biginf = 1e18;
const int maxN = 5 * 1e5 + 5;

vector<pii> g[maxN];
map<int, int> dp[maxN];
int n, k, dep[maxN], sum[maxN], ans = inf;
void dfs(int v, int par, int len, int val) {
    dep[v] = len; sum[v] = val;
    dp[v][sum[v]] = dep[v];
    for (pii u : g[v]) {
        if (u.ff == par) continue;
        dfs(u.ff, v, len + 1, val + u.sc);
        if (dp[u.ff].size() > dp[v].size())
            swap(dp[u.ff], dp[v]);
        for (auto x : dp[u.ff]) {
            if (dp[v].find(k + 2 * sum[v] - x.ff) != dp[v].end()) {
                ans = min(ans, dp[v][k + 2 * sum[v] - x.ff] + x.sc - 2 * dep[v]);
            }
        } for (auto x : dp[u.ff]) {
            if (dp[v].find(x.ff) == dp[v].end())
                dp[v][x.ff] = x.sc;
            else dp[v][x.ff] = min(dp[v][x.ff], x.sc);
        }
    }
}
int best_path(int _n, int _k, int h[][2], int l[]) {
    n = _n; k = _k;
    for (int i = 0; i < n - 1; i++) {
        g[h[i][0]].pb({h[i][1], l[i]});
        g[h[i][1]].pb({h[i][0], l[i]});
    } dfs(0, -1, 0, 0);
    return (ans == inf ? -1 : ans);
}
// int main() {
//     int _n, _k;
//     cin >> _n >> _k;
//     int h[_n][2], l[_n];
//     for (int i = 0; i < _n - 1; i++) {
//         cin >> h[i][0] >> h[i][1];
//     } for (int i = 0; i < _n - 1; i++) cin >> l[i];
//     cout << best_path(_n, _k, h, l);
// }

Compilation message (stderr)

race.cpp: In function 'void open_file(std::string)':
race.cpp:26:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   26 |     freopen((filename + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
race.cpp:27:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |     freopen((filename + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 12 / 12
• Subtask 3: 22 / 22
• Subtask 4: 57 / 57