Submission #1004617

#	Time	Username	Problem	Language	Result	Execution time	Memory
1004617		Whisper	Parkovi (COCI22_parkovi)	C++17	110 / 110	1056 ms	44996 KiB

Main

#include <bits/stdc++.h>

using namespace std;
using ll = long long;

#define int long long
#define FOR(i, a, b) for (int i = (a); i <= (b); i++)
#define FORD(i, a, b) for (int i = (b); i >= (a); i --)
#define REP(i, n) for (int i = 0; i < (n); ++i)
#define REPD(i, n) for (int i = (n) - 1; i >= 0; --i)

#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)


constexpr ll LINF = (1ll << 60);
constexpr int INF = (1ll << 30);
constexpr int Mod = 1e9 + 7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

/*
    Phu Trong from Nguyen Tat Thanh High School for gifted student
*/

template <class X, class Y>
    bool minimize(X &x, const Y &y){
        X eps = 1e-9;
        if (x > y + eps) {x = y; return 1;}
        return 0;
    }

template <class X, class Y>
    bool maximize(X &x, const Y &y){
        X eps = 1e-9;
        if (x + eps < y) {x = y; return 1;}
        return 0;
    }
#define MAX     200005
struct Edge{
    int u, v, w;
    Edge(){}
    Edge(int _u, int _v, int _w): u(_u), v(_v), w(_w){}

    int other(int x){return (x ^ u ^ v);}
} edge[MAX];

int numNode, k;
vector<int> G[MAX];

void loadGraph(void){
    cin >> numNode >> k;
    for (int i = 1; i < numNode; ++i){
        cin >> edge[i].u >> edge[i].v >> edge[i].w;
        G[edge[i].u].emplace_back(i);
        G[edge[i].v].emplace_back(i);
    }
}

int minDist[MAX], maxReach[MAX];

vector<int> candidate;

void dfs(int u, int p, int d){
    for (int &i : G[u]){
        int v = edge[i].other(u);
        if(v ^ p){
            dfs(v, u, d);
            if (maxReach[v] + min(edge[i].w, minDist[v]) <= d){
                if (maxReach[v] + minDist[v] > d)
                    maximize(maxReach[u], maxReach[v] + edge[i].w);
                minimize(minDist[u], minDist[v] + edge[i].w);
            }
            else{
                candidate.emplace_back(v);
                minimize(minDist[u], edge[i].w);
            }
        }
    }
}

bool check(int d){
    candidate.clear();
    memset(maxReach, 0, (numNode + 1) * sizeof(int));
    memset(minDist, 0x3f, (numNode + 1) * sizeof(int));
    dfs(1, -1, d);
    if (maxReach[1] + minDist[1] > d) candidate.push_back(1);
    return (int)candidate.size() <= k;
}


int chosen[MAX];
void process(void){
    int l = 0, r = 1e15;
    while(r - l > 1){
        int m = (l + r) >> 1;
        if(check(m)) r = m;
        else l = m;
    }

    cout << r << '\n';
    check(r);
    for (int& v : candidate) chosen[v] = 1;
    for (int i = 1; i <= numNode; ++i) {
        if(!chosen[i] && (int)candidate.size() < k)
            candidate.push_back(i);
    }
    for (int &v : candidate) cout << v << " ";
}
signed main(){
    #define name "Whisper"
    cin.tie(nullptr) -> sync_with_stdio(false);
    //freopen(name".inp", "r", stdin);
    //freopen(name".out", "w", stdout);
    loadGraph();
    process();
}

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 30 / 30
• Subtask 4: 60 / 60