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Submission #1081786

# Submission time Handle Problem Language Result Execution time Memory
1081786 2024-08-30T10:44:25 Z vladilius Highway Tolls (IOI18_highway) C++17
51 / 100
 120 ms 23988 KB 
#include "highway.h"
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
#define pb push_back
#define ff first
#define ss second

void find_pair(int n, vector<int> U, vector<int> V, int A, int B){
    int m = (int) U.size();
    vector<pii> g[n + 1];
    for (int i = 0; i < m; i++){
        U[i]++; V[i]++;
        g[U[i]].pb({V[i], i});
        g[V[i]].pb({U[i], i});
    }
    
    vector<int> w(m);

    ll nl = ask(w);
    int l = 0, r = m - 1;
    while (l + 1 < r){
        int k = (l + r) / 2;
        fill(w.begin(), w.end(), 0);
        for (int i = k + 1; i < m; i++) w[i] = 1;
        if (ask(w) == nl){
            r = k;
        }
        else {
            l = k + 1;
        }
    }
    
    fill(w.begin(), w.end(), 0);
    for (int i = l + 1; i < m; i++) w[i] = 1;
    if (ask(w) == nl){
        r = l;
    }
    int x = r;

    vector<bool> used(n + 1);
    vector<int> ed = {x};
    queue<int> q;
    q.push(V[x]);
    q.push(U[x]);
    used[V[x]] = used[U[x]] = 1;
    while (!q.empty()){
        int f = q.front(); q.pop();
        for (auto [i, j]: g[f]){
            if (used[i] || j == x) continue;
            used[i] = 1;
            q.push(i);
            ed.pb(j);
        }
    }
    
    fill(w.begin(), w.end(), 1);
    
    auto cl = [&](){
        for (int i: ed) w[i] = 0;
    };
    
    cl();
    vector<pii> t[n + 1];
    for (int i: ed){
        t[U[i]].pb({V[i], i});
        t[V[i]].pb({U[i], i});
    }
    
    vector<int> d(n + 1), p(n + 1), pe(n + 1);
    function<void(int, int, vector<int>&, vector<int>&)> dfs = [&](int v, int pr, vector<int>& ed, vector<int>& q){
        q.pb(v);
        p[v] = pr;
        for (auto [i, j]: t[v]){
            if (i == pr || j == x) continue;
            d[i] = d[v] + 1;
            pe[i] = j;
            ed.pb(j);
            dfs(i, v, ed, q);
        }
    };
    
    vector<int> d1, d2, t1, t2;
    dfs(U[x], 0, d1, t1);
    dfs(V[x], 0, d2, t2);
    
    int dist = (int) (ask(w) / A);
    
    auto add = [&](int x, int y){
        while (y != x && !w[pe[y]]){
            w[pe[y]] = 1;
            y = p[y];
        }
    };
    
    auto solve = [&](int v, vector<int>& x1, vector<int>& x2, vector<int>& vv){
        cl();
        for (int i: x2) w[i] = 1;
        int ds = (int) ((ask(w) + B - A - 1LL * dist * B) / (A - B));
        
        vector<int> all;
        for (int i: vv){
            if (d[i] == ds){
                all.pb(i);
            }
        }
        
        while (all.size() > 1){
            int k = (int) all.size() / 2;
            cl();
            for (int i = 0; i < k; i++){
                add(v, all[i]);
            }
            ll sm = ask(w);
            if (sm == (1LL * A * (dist - ds) + 1LL * B * ds)){
                while (all.size() > k){
                    all.pop_back();
                }
            }
            else {
                reverse(all.begin(), all.end());
                k = (int) all.size() - k;
                while (all.size() > k) all.pop_back();
            }
        }
        
        return (all[0] - 1);
    };
    
    answer(solve(U[x], d1, d2, t1), solve(V[x], d2, d1, t2));
}

Compilation message

highway.cpp: In lambda function:
highway.cpp:117:35: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  117 |                 while (all.size() > k){
      |                        ~~~~~~~~~~~^~~
highway.cpp:124:35: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  124 |                 while (all.size() > k) all.pop_back();
      |                        ~~~~~~~~~~~^~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 1 ms 344 KB Output is correct
3 Correct 1 ms 344 KB Output is correct
4 Correct 1 ms 344 KB Output is correct
5 Correct 0 ms 344 KB Output is correct
6 Correct 0 ms 344 KB Output is correct
7 Correct 1 ms 344 KB Output is correct
8 Correct 0 ms 344 KB Output is correct
9 Correct 0 ms 344 KB Output is correct
10 Correct 0 ms 344 KB Output is correct
11 Correct 0 ms 344 KB Output is correct
12 Correct 0 ms 344 KB Output is correct

Subtask #2
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 600 KB Output is correct
2 Correct 10 ms 2136 KB Output is correct
3 Correct 103 ms 15804 KB Output is correct
4 Correct 99 ms 15840 KB Output is correct
5 Correct 92 ms 15804 KB Output is correct
6 Correct 104 ms 15660 KB Output is correct
7 Correct 90 ms 15792 KB Output is correct
8 Correct 102 ms 15608 KB Output is correct
9 Correct 106 ms 16260 KB Output is correct
10 Correct 90 ms 16104 KB Output is correct
11 Correct 91 ms 16560 KB Output is correct
12 Correct 100 ms 17940 KB Output is correct
13 Correct 88 ms 17080 KB Output is correct
14 Correct 95 ms 17540 KB Output is correct

Subtask #3
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 2904 KB Output is correct
2 Correct 16 ms 4892 KB Output is correct
3 Correct 25 ms 7756 KB Output is correct
4 Correct 75 ms 20028 KB Output is correct
5 Correct 71 ms 20916 KB Output is correct
6 Correct 76 ms 22912 KB Output is correct
7 Correct 75 ms 23988 KB Output is correct
8 Correct 74 ms 20560 KB Output is correct
9 Correct 72 ms 22156 KB Output is correct

Subtask #4
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 600 KB Output is correct
2 Correct 10 ms 2044 KB Output is correct
3 Correct 70 ms 12404 KB Output is correct
4 Correct 88 ms 15748 KB Output is correct
5 Correct 91 ms 15580 KB Output is correct
6 Correct 81 ms 15828 KB Output is correct
7 Correct 84 ms 15712 KB Output is correct
8 Correct 82 ms 15756 KB Output is correct
9 Correct 94 ms 15372 KB Output is correct
10 Correct 92 ms 15732 KB Output is correct
11 Correct 90 ms 16536 KB Output is correct
12 Correct 99 ms 17588 KB Output is correct
13 Correct 89 ms 16812 KB Output is correct
14 Correct 90 ms 17240 KB Output is correct
15 Correct 86 ms 15588 KB Output is correct
16 Correct 83 ms 15604 KB Output is correct
17 Correct 97 ms 17120 KB Output is correct
18 Correct 89 ms 17288 KB Output is correct
19 Correct 80 ms 15712 KB Output is correct
20 Correct 90 ms 18104 KB Output is correct
21 Correct 82 ms 16676 KB Output is correct
22 Correct 87 ms 16496 KB Output is correct
23 Correct 85 ms 16164 KB Output is correct
24 Correct 96 ms 16812 KB Output is correct
25 Correct 120 ms 23168 KB Output is correct

Subtask #5
0 / 18.0

# Verdict Execution time Memory Grader output
1 Incorrect 9 ms 2136 KB Output is incorrect: {s, t} is wrong.
2 Halted 0 ms 0 KB -

Subtask #6
0 / 31.0

# Verdict Execution time Memory Grader output
1 Incorrect 12 ms 2136 KB Output is incorrect: {s, t} is wrong.
2 Halted 0 ms 0 KB -