Submission #372764

#	Time	Username	Problem	Language	Result	Execution time	Memory
372764		Lightning	Race (IOI11_race)	C++14	Compilation error	0 ms	0 KiB

race

//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,sse3,sse4,popcnt,abm,mmx")

#include "race.h"
#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>
#include <set>
#include <map>
#include <iomanip>
#include <cassert>
#include <stack>
#include <queue>
#include <deque>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>-

using namespace std;
//using namespace __gnu_pbds;

typedef long long ll;
#define int ll
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;

// template<typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
//  order_of_key (k) : Number of items strictly smaller than k .
//  find_by_order(k) : K-th element in a set (counting from zero).
#define sz(a) (int)a.size()
#define all(a) a.begin(), a.end()
#define pb push_back
#define ppb pop_back
#define mkp make_pair
#define F first
#define S second
#define lb lower_bound
#define ub upper_bound
#define show(a) cerr << #a <<" -> "<< a <<" "
#define nl cerr <<"\n"


const int MAXN = 2e5 + 5;
const int oo = 1e18 + 5;

int n, k, h[MAXN][2], l[MAXN];
vector <pii> g[MAXN];
int sz[MAXN], ans = oo;
bool del[MAXN];
set <pii> st;

void calcSZ(int v, int pr = -1) {
    sz[v] = 1;
    for (pii x : g[v]) {
        int to = x.F;
        if (to == pr || del[to]) { continue; }
        calcSZ(to, v);
        sz[v] += sz[to];
    }
}

int findCentroid(int v, int pr = -1) {
    for (pii x : g[v]) {
        int to = x.F;
        if (to == pr || del[to]) { continue; }
        if (sz[to] > sz[v] / 2) {
            sz[v] -= sz[to];
            sz[to] += sz[v];
            return findCentroid(to, v);
        }
    }
    return v;
}

void update(int v, int pr, int lvl, int d) {
    st.insert({d, lvl});
    for (pii x : g[v]) {
        int to = x.F, w = x.S;
        if (to == pr || del[to]) { continue; }
        update(to, v, lvl + 1, d + w);
    }
}

void query(int v, int pr, int lvl, int d) {
    auto it = st.lower_bound({k - d, 0ll});
    if (it != st.end()) {
        int d2 = it -> F, lvl2 = it -> S;
        if (d + d2 == k) {
            ans = min(ans, lvl + lvl2);
        }
    }
    for (pii x : g[v]) {
        int to = x.F, w = x.S;
        if (to == pr || del[to]) { continue; }
        query(to, v, lvl + 1, d + w);
    }
}

void travel(int root) {
    calcSZ(root);
    int c = findCentroid(root);
    st.insert({0, 0});
    for (pii x : g[c]) {
        int to = x.F, w = x.S;
        if (del[to]) { continue; }
        query(to, c, 1, w);
        update(to, c, 1, w);
    }
    st.clear();
    del[c] = 1;
    for (pii x : g[c]) {
        int to = x.F;
        if (del[to]) { continue; }
        travel(to);
    }
}

int best_path(int N, int K, int H[][2], int L[]) {
    n = N, k = K;
    for (int i = 0; i < n-1; ++i) {
        h[i][0] = H[i][0];
        h[i][1] = H[i][1];
    }
    for (int i = 0; i < n-1; ++i) {
        l[i] = L[i];
        int a = h[i][0], b = h[i][1], w = l[i];
        g[a].pb({b, w});
        g[b].pb({a, w});
    }

    travel(0);

    if (ans == oo) { return -1; }
    return ans;
}

/*
4 3
0 1
1 2
1 3
1
2
4

2
---------------------------
3 3
0 1
1 2
1
1

-1
---------------------------
11 12
0 1
0 2
2 3
3 4
4 5
0 6
6 7
6 8
8 9
8 10
3
4
5
4
6
3
2
5
6
7

2
*/

Compilation message (stderr)

/tmp/cch6kswz.o: In function `main':
grader.cpp:(.text.startup+0x24): undefined reference to `best_path(int, int, int (*) [2], int*)'
collect2: error: ld returned 1 exit status