Submission #863406

#	Time	Username	Problem	Language	Result	Execution time	Memory
863406		boris_mihov	Truck Driver (IOI23_deliveries)	C++17	29 / 100	5521 ms	19764 KiB

deliveries

#include "deliveries.h"
#include <algorithm>
#include <iostream>
#include <numeric>
#include <cassert>
#include <vector>

typedef long long llong;
const int MAXN = 100000 + 10;
const int INF  = 1e9;

int n;
int w[MAXN];
llong sz[MAXN], sum;
std::vector <std::pair <int,int>> g[MAXN];

void init(int N, std::vector<int> U, std::vector<int> V, std::vector<int> T, std::vector<int> W)
{
    n = N;
    for (int i = 0 ; i < n - 1 ; ++i)
    {
        g[U[i]].push_back({V[i], T[i]});
        g[V[i]].push_back({U[i], T[i]});
    }

    for (int i = 0 ; i < n ; ++i)
    {
        w[i] = W[i];
        sum += w[i];
    }

    w[0]++;
    sum++;
}

void fixDFS(int node, int par)
{
    sz[node] = w[node];
    for (const auto &[u, d] : g[node])
    {
        if (u == par)
        {
            continue;
        }

        fixDFS(u, node);
        sz[node] += sz[u];
    }
}

int findDFS(int node, int par)
{
    for (const auto &[u, d] : g[node])
    {
        if (u == par)
        {
            continue;
        }

        if (sz[u] > sum / 2)
        {
            return findDFS(u, node);
        }
    }

    return node;
}

llong calcDFS(int node, int par, llong currD)
{
    llong res = currD * w[node];
    for (const auto &[u, d] : g[node])
    {
        if (u == par)
        {
            continue;
        }

        res += calcDFS(u, node, currD + d);
    }

    return res;
}

long long max_time(int S, int X) 
{
    sum -= w[S];
    w[S] = X;
    if (S == 0) w[S]++;
    sum += w[S];
    fixDFS(0, -1);
	return 2 * calcDFS(findDFS(0, -1), -1, 0);
}

• Subtask 1: 8 / 8
• Subtask 2: 21 / 21
• Subtask 3: 0 / 14
• Subtask 4: 0 / 21
• Subtask 5: 0 / 36