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Submission #1037974

# Submission time Handle Problem Language Result Execution time Memory
1037974 2024-07-29T11:31:58 Z karok Race (IOI11_race) C++17
0 / 100
 2 ms 9052 KB 
#include <bits/stdc++.h>
using namespace std;

struct Edges {
    int target, weight;
};

const int MAXN = 200000;
const int MAXK = 1000000;

int n, k;
vector<vector<Edges>> adj(MAXN);
int tree_size[MAXN] = {};
bool is_removed[MAXN];

int get_tree_size(int cur_vertex, int parent = -1) {
    int &res = tree_size[cur_vertex];
    res = 1;
    for (auto [v, w] : adj[cur_vertex]) {
        if (v == parent || is_removed[v])continue;
            continue;
        res += get_tree_size(v, cur_vertex);
    }
    return res;
}

int get_centroid(int cur_vertex, int n, int parent = -1) {
    for (auto [v, w] : adj[cur_vertex]) {
        if (parent == v || is_removed[v])
            continue;
        if (tree_size[v] * 2 > n)
            return get_centroid(v, n, cur_vertex);
    }
    return cur_vertex;
}

int dfs(int cur_v,int cur_length, int total_ans, set<int> &past_lengths, int parent = -1){
    int res = INT_MAX;
    if(past_lengths.count(k - cur_length)) {
        return total_ans;
    }
    for(auto [v, w]: adj[cur_v]){
        if(v == parent || is_removed[v]) continue;
        res = min(dfs(v, w + cur_length, total_ans + 1, past_lengths, cur_v), res);
    }
    past_lengths.insert(cur_length);
    return res;
}

int centroid_dfs(int cur_v) {
    int centroid = get_centroid(cur_v, get_tree_size(cur_v));
    int res;
    {
        set<int> lengths{0};
        res = dfs(centroid, 0, 0, lengths);
    }
    is_removed[centroid] = true;
    for(auto [u, w]: adj[centroid]) {
        if(is_removed[u])continue;
        res = min(centroid_dfs(u), res);
    }
    return res;
}

int best_path(int a, int b, int h[][2] ,int l[] ) {
    n = a; k= b;
    for(int i =0;i < n - 1;i++) {
        adj[h[i][0]].push_back( Edges{h[i][1], l[i]} );
        adj[h[i][1]].push_back( Edges{h[i][0], l[i]} );
    }
    return centroid_dfs(0);
}

Subtask #1
0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 9052 KB Output is correct
2 Correct 2 ms 9052 KB Output is correct
3 Incorrect 2 ms 9052 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #2
0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 9052 KB Output is correct
2 Correct 2 ms 9052 KB Output is correct
3 Incorrect 2 ms 9052 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #3
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 9052 KB Output is correct
2 Correct 2 ms 9052 KB Output is correct
3 Incorrect 2 ms 9052 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #4
0 / 57.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 9052 KB Output is correct
2 Correct 2 ms 9052 KB Output is correct
3 Incorrect 2 ms 9052 KB Output isn't correct
4 Halted 0 ms 0 KB -