Submission #636724

#	Time	Username	Problem	Language	Result	Execution time	Memory
636724		rainliofficial	Race (IOI11_race)	C++17	9 / 100	124 ms	33080 KiB

race

#include <bits/stdc++.h>
#include "race.h"
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
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 a < b ? a = b, 1 : 0; }
#define sz(x) (int)x.size()

void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x);
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? ", " : ""), __print(i); cerr << "}";}
template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ", "; __print(x.second); cerr << '}';}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef DEBUG
#define dbg(x...) cerr << "\e[91m"<<__func__<<":"<<__LINE__<<" [" << #x << "] = ["; _print(x); cerr << "\e[39m" << endl;
#else
#define dbg(x...)
#endif

const int MAXN = 2e5+5, INF = 1e9;
int n, k, ans = INF, h[MAXN][2], l[MAXN], dep[MAXN];
vector<pii> arr[MAXN];
set<pii> vals[MAXN];
pii offset[MAXN];

void solve(int at, int parent, int cost, int d = 0){
    // Find the largest subtree
    int big = at, bigCost = 0;
    dep[at] = d;
    for (pii i : arr[at]){
        if (i.first != parent){
            solve(i.first, at, i.second, d+1);
            if (vals[i.first].size() > vals[big].size()){
                big = i.first;
                bigCost = i.second;
            }
        }
    }
    
    if (at != big){
        swap(vals[at], vals[big]); // Copy the largest subtree
        offset[at] = offset[big];
        offset[at].first += bigCost;
        offset[at].second++;
    }
    // Manually add the remaining elements
    for (pii i : arr[at]){
        if (i.first != parent && i.first != big){ // Since vals[big] is empty now (we called swap() on it), we don't have to worry about it anymore
            for (pii x : vals[i.first]){
                int costNeeded = k - (x.first + offset[i.first].first + i.second) - offset[at].first;
                int adjDist = x.second + offset[i.first].second + 1;
                auto it = vals[at].lower_bound({costNeeded, -INF});
                if (it != vals[at].end() && (*it).first == costNeeded){
                    ckmin(ans, (*it).second + offset[at].second + adjDist);
                }
            }
            for (pii x : vals[i.first]){
                int adjCost = (x.first + offset[i.first].first + i.second) - offset[at].first;
                int adjDist = x.second + offset[i.first].second - offset[at].second;
                vals[at].insert({adjCost, adjDist});
            }
        }
    }

    auto it = vals[at].lower_bound({k - offset[at].first, -INF});
    if (it != vals[at].end() && (*it).first == k - offset[at].first){
        ckmin(ans, (*it).second + offset[at].second);
        // dbg(ans, at, offset[at].first, (*it), offset[at].second)
    }
        
    vals[at].insert({-offset[at].first, -offset[at].second});
}

int best_path(int N, int K, int h[][2], int l[]){
    n = N, k = K;
    for (int i=0; i<n-1; i++){
        int a = h[i][0], b = h[i][1];
        arr[a].push_back({b, l[i]});
        arr[b].push_back({a, l[i]});
    }
    solve(0, -1, 0);
    return ans != INF ? ans : -1;
}

• Subtask 1: 9 / 9
• Subtask 2: 0 / 12
• Subtask 3: 0 / 22
• Subtask 4: 0 / 57