Submission #1005686

#	Time	Username	Problem	Language	Result	Execution time	Memory
1005686		whatthemomooofun1729	Traffic (IOI10_traffic)	C++17	100 / 100	594 ms	159056 KiB

traffic

#include "traffic.h"
#include <iostream>
#include <algorithm>
#include <utility>
#include <vector>
#include <stack>
#include <map>
#include <queue>
#include <set>
#include <unordered_set>
#include <unordered_map>
#include <cstring>
#include <cmath>
#include <functional>
#include <cassert>
#include <iomanip>
#include <numeric>
#include <bitset>
#include <sstream>
#include <chrono>
#include <random>

#define ff first
#define ss second
#define PB push_back
#define sz(x) int(x.size())
#define rsz resize
#define fch(xxx, yyy) for (auto xxx : yyy) // abusive notation
#define all(x) (x).begin(),(x).end()
#define eps 1e-9

// more abusive notation (use at your own risk):
// #define int ll

using namespace std;
typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vll = vector<ll>;

// debugging
void __print(int x) {std::cerr << x;}
void __print(ll x) {std::cerr << x;} /* remember to uncomment this when not using THE MACRO */
void __print(unsigned x) {std::cerr << x;}
void __print(ull x) {std::cerr << x;}
void __print(float x) {std::cerr << x;}
void __print(double x) {std::cerr << x;}
void __print(ld x) {std::cerr << x;}
void __print(char x) {std::cerr << '\'' << x << '\'';}
void __print(const char *x) {std::cerr << '\"' << x << '\"';}
void __print(const string& x) {std::cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
template<typename T, typename V> void __print(const pair<T, V> &x) {std::cerr << '{'; __print(x.ff); std::cerr << ", "; __print(x.ss); std::cerr << '}';}
template<typename T> void __print(const T& x) {int f = 0; std::cerr << '{'; for (auto &i: x) std::cerr << (f++ ? ", " : ""), __print(i); std::cerr << "}";}
void _print() {std::cerr << "]\n";}
template <typename T, typename... V> void _print(T t, V... v) {__print(t); if (sizeof...(v)) std::cerr << ", "; _print(v...);}
void println() {std::cerr << ">--------------------<" << endl;}
#ifndef ONLINE_JUDGE
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif

// templates
template <class T> bool ckmin(T &a, const T &b) {return b<a ? a = b, 1 : 0;}
template <class T> bool ckmax(T &a, const T &b) {return b>a ? a = b, 1 : 0;}
template <class T> using gr = greater<T>;
template <class T> using vc = vector<T>;
template <class T> using p_q = priority_queue<T>;
template <class T> using pqg = priority_queue<T, vc<T>, gr<T>>;
template <class T1, class T2> using pr = pair<T1, T2>;
mt19937_64 rng_ll(chrono::steady_clock::now().time_since_epoch().count());
int rng(int M) {return (int)(rng_ll()%M);} /*returns any random number in [0, M) */

// const variables
constexpr int INF = (int)2e9;
constexpr int MOD = 1e9 + 9;
constexpr ll LL_INF = (ll)3e18;
constexpr int mod = (int)1e9 + 7;
constexpr ll inverse = 500000004LL; // inverse of 2 modulo 1e9 + 7

void setIO(const string& str) {// fast input/output
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    if (str.empty()) return;
    freopen((str + ".in").c_str(), "r", stdin);
    freopen((str + ".out").c_str(), "w", stdout);
}

int N;
vi a, dp, par;
vc<vi> adj;

void dfs(int v, int pr) {
    dp[v] = a[v];
    par[v] = pr;
    fch(u, adj[v]) if (u != pr) {
        dfs(u, v);
        dp[v] += dp[u];
    }
}

int LocateCentre(int n, int p[], int s[], int d[]) {
    N = n;
    adj.rsz(N), a.rsz(N), dp.rsz(N, 0), par.rsz(N, -1);
    int tot = 0;
    for (int i = 0; i < N; ++i) {
        a[i] = p[i];
        tot += a[i];
    }
    for (int i = 0; i < N - 1; ++i) {
        adj[s[i]].PB(d[i]);
        adj[d[i]].PB(s[i]);
    }
    dfs(0, -1);
    int c = INF + 1, idx = -1;
    for (int i = 0; i < N; ++i) {
        if (i == 0) {
            int C = 0;
            fch(u, adj[i]) {
                ckmax(C, dp[u]);
            }
            if (ckmin(c, C)) {
                idx = i;
            }
        } else {
            int C = tot - dp[i];
            fch(u, adj[i]) {
                if (u == par[i]) continue;
                ckmax(C, dp[u]);
            }
            if (ckmin(c, C)) {
                idx = i;
            }
        }
    }
    return idx;
}
/*
int n;
int p[100005];
int s[100005];
int d[100005];

signed main() { // TIME YOURSELF !!!
    setIO("");
    cin >> n;
    for (int i = 0; i < n; ++i) {
        cin >> p[i];
    }
    for (int i = 0; i < n - 1; ++i) {
        int awef, fewa;
        cin >> awef >> fewa;
        s[i] = awef, d[i] = fewa;
    }
    cout << LocateCentre(n, p, s, d) << '\n';
    return 0;
}*/

// TLE -> TRY NOT USING DEFINE INT LONG LONG
// CE -> CHECK LINE 45
// 5000 * 5000 size matrices are kinda big (potential mle)
// Do something, start simpler

Compilation message (stderr)

traffic.cpp: In function 'void setIO(const string&)':
traffic.cpp:89:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   89 |     freopen((str + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
traffic.cpp:90:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   90 |     freopen((str + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 25 / 25
• Subtask 2: 25 / 25
• Subtask 3: 25 / 25
• Subtask 4: 25 / 25