Submission #543865

#	Time	Username	Problem	Language	Result	Execution time	Memory
543865		AJ00	Race (IOI11_race)	C++14	Compilation error	0 ms	0 KiB

race

#include <bits/stdc++.h>
//#include "race.h"
using namespace std;
//#define ll long long 
#define ll long long 
const ll MAXN = 200001;
const ll LOGN = 20;
vector<vector<pair<ll,ll>>> adj(MAXN);
int depth[MAXN];
ll par[MAXN][LOGN],weight[MAXN][LOGN];
pair<ll,int> lca(ll x, ll y){
    ll X = x, Y = y;
    if (depth[X] < depth[Y]){
        swap(x,y);
        swap(X,Y);
    }
    ll dh = depth[x]-depth[y];
    ll totw = 0;
    for (ll i = LOGN-1; i >= 0; i--){
        if (dh&(1<<i)){
            totw += weight[x][i];
            x = par[x][i];
        }
    }
    if (x == y){
        return {totw, depth[X]-depth[Y]};
    }
    int lvl = 0;
    for (ll i = LOGN; i >= 0; i--){
        if (par[x][i] != par[y][i]){
            totw += weight[x][i];
            totw += weight[y][i];
            lvl += (1<<i);
            x = par[x][i];
            y = par[y][i];
        }
    }
    totw += weight[x][0];
    totw += weight[y][0];
    lvl += 1;
    lvl *= 2;
    return {totw,lvl+depth[X]-depth[Y]};
}
void dfs(ll x, ll h = 0, ll p= 0, ll w = 0){
    depth[x] = h;
    par[x][0] = p;
    weight[x][0] = w;
    for (ll i = 1; i < LOGN; i++){
        par[x][i] = par[par[x][i-1]][i-1];
        weight[x][i] = weight[x][i-1] + weight[par[x][i-1]][i-1];
    }
    for (auto ch: adj[x]){
        ll t = ch.first;
        ll wt = ch.second;
        if (t != p){
            dfs(t,h+1,x,wt);
        }
    }
}
int best_path(ll N,ll K,ll H[][2],ll L[]){
    for (ll i = 0; i < N-1; i++){
        adj[H[i][0]].push_back({H[i][1],L[i]});
        adj[H[i][1]].push_back({H[i][0],L[i]});
    }
    dfs(0);
    int ans = N;
    for (ll i = 0; i < N; i++){
        for (ll j = i+1; j < N; j++){
            pair<ll,int> l = lca(i,j);
            if (l.first == K){
               // cout << i << " " << j << " " << depth[i] << " " << depth[j] << "\n";
                ans = min(ans,l.second);
            }
        }
    }
    ans -= (ans == N ? N+1 : 0);
    return ans;
}

Compilation message (stderr)

/usr/bin/ld: /tmp/ccJzSwYx.o: in function `main':
grader.cpp:(.text.startup+0x28): undefined reference to `best_path(int, int, int (*) [2], int*)'
collect2: error: ld returned 1 exit status