oj.uz

Submission #75067

# Submission time Handle Problem Language Result Execution time Memory
75067 2018-09-08T08:23:48 Z dacin21 Highway Tolls (IOI18_highway) C++14
90 / 100
 753 ms 33284 KB 
#include "highway.h"



#include <bits/stdc++.h>
using namespace std;
using ll = long long;


mt19937 rng(135785932);
int get_rand(int l, int r){
    return uniform_int_distribution<int>(l, r)(rng);
}

int A, B, C, M, n;
ll initial;
int path_len;
int ed;
vector<vector<pair<int, int> > > g;
map<pair<int, int>, int> deco;



vector<char> state;
vector<int> gord;

bool rec(int u, int p, int pared){
    assert(state[u] == 0);
    state[u] = 1;
    int pool = -1;
    auto add_cand = [&](int e){
        if(pool == -1){
            pool = e;
        } else {
            gord.push_back(pool);
            gord.push_back(e);
            pool = -1;
        }
    };
    for(auto const&e:g[u]){
        if(e.first == p) continue;
        if(state[e.first] == 0){
            bool did = rec(e.first, u, e.second);
            if(!did){
                add_cand(e.second);
            }
        } else if(state[e.first] == 1){
            add_cand(e.second);
        }
    }
    state[u] = 2;
    if(pool != -1){
        gord.push_back(pool);
        gord.push_back(pared);
        return true;
    }
    return false;
}

vector<int> line_graph_allign(){
    state.assign(n, 0);
    gord.clear();

    rec(get_rand(0, n-1), -1, -1);

    if(M%2){
        assert(gord.back() == -1);
        gord.pop_back();
        gord.push_back(gord.back());
    }

    return gord;
}


int find_vertex(int M, vector<int> const&U, vector<int> const&V){
    vector<int> ord = line_graph_allign();
    for(int i=0;i<ord.size();i+=2){
        int j = 2*get_rand(0, i/2);
        swap(ord[i], ord[i-j]);
        swap(ord[i+1], ord[i-j+1]);
    }
    /*for(int i=0;i<ord.size();i+=2){
        cerr << U[ord[i]] << " " << V[i] << " | " << U[i+1] << " " << V[i+1] << "\n";
    }*/
    int l = -1, r = (M+1)/2-1;
    while(l+1 < r){
        int m = l + (r-l)/2;

        vector<int> v(M, 1);
        for(int i=0;i/2<=m;++i) v[ord[i]] = 0;
        ll mid = ask(v);
        if(mid == path_len*(ll)A){
            r = m;
        } else {
            l = m;
        }
    }
    map<int, int> cnt;
    for(auto const&e:{U, V}){
        for(auto const&i:{ord[2*r], ord[2*r+1]}){
            ++cnt[e[i]];
        }
    }
    for(auto const&e:cnt){
        if(e.second == 2){
            return e.first;
        }
    }
    assert(0);
    return -1;

}
int far_search(int u, vector<int> const&U, vector<int> const&V, bool fix_d){
    vector<int> ord, vis(n, 0);
    vector<int> inv_ord(n);
    vector<int> d;
    ord.push_back(u);
    d.push_back(0);
    vis[u] = 1;
    for(int i=0;i<(int)ord.size();++i){
        int v = ord[i];
        inv_ord[v] = i;
        for(auto const&f:g[v]){
            auto const e = f.first;
            if(!vis[e]){
                vis[e] = 1;
                ord.push_back(e);
                d.push_back(d[i]+1);
            }
        }
    }
    assert((int)ord.size() == n);
    int l = 0, r = n;
    if(fix_d){
        l = lower_bound(d.begin(), d.end(), path_len) - d.begin();
        r = upper_bound(d.begin(), d.end(), path_len) - d.begin();
    }
    while(l+1 < r){
        int m = l + (r-l)/2;
        vector<int> v(M, 1);
        for(int i=0;i<M;++i){
            if(inv_ord[U[i]] < m && inv_ord[V[i]] < m){
                v[i] = 0;
            }
        }
        ll dist = ask(v);
        if(dist == path_len * (ll) A){
            r = m;
        } else {
            l = m;
        }
    }
    return ord[l];
}


void find_pair(int N, vector<int> U, vector<int> V, int A_, int B_) {
    n=N; A=A_; B=B_;
    C = B-A;
    M = U.size();
    for(int i=0;i<M;++i){
        deco[make_pair(U[i], V[i])] = i;
        deco[make_pair(V[i], U[i])] = i;
    }
    initial = ask(vector<int>(M, 1));
    assert(initial % B == 0);
    path_len = initial / B;
    //if(path_len <= 2) ask(vector<int>(M, 1));
    g.assign(N, vector<pair<int, int> >());
    for(int i=0;i<M;++i){
        g[U[i]].emplace_back(V[i], i);
        g[V[i]].emplace_back(U[i], i);
    }
    for(auto &e:g) shuffle(e.begin(), e.end(), rng);

    int start = find_vertex(M, U, V);
    //cerr << "ed " << ed << " : " << U[ed] << " " << V[ed] << "\n";
    const int S = far_search(start, U, V, false);
    const int T = far_search(S, U, V, true);
    answer(S, T);
}

Compilation message

highway.cpp: In function 'int find_vertex(int, const std::vector<int>&, const std::vector<int>&)':
highway.cpp:78:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<ord.size();i+=2){
                 ~^~~~~~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 376 KB Output is correct
2 Correct 2 ms 248 KB Output is correct
3 Correct 2 ms 376 KB Output is correct
4 Correct 2 ms 376 KB Output is correct
5 Correct 2 ms 376 KB Output is correct
6 Correct 2 ms 248 KB Output is correct
7 Correct 2 ms 248 KB Output is correct
8 Correct 2 ms 376 KB Output is correct
9 Correct 2 ms 420 KB Output is correct
10 Correct 2 ms 424 KB Output is correct
11 Correct 2 ms 340 KB Output is correct
12 Correct 2 ms 332 KB Output is correct

Subtask #2
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 464 KB Output is correct
2 Correct 54 ms 2632 KB Output is correct
3 Correct 375 ms 21212 KB Output is correct
4 Correct 353 ms 21212 KB Output is correct
5 Correct 499 ms 21208 KB Output is correct
6 Correct 366 ms 21220 KB Output is correct
7 Correct 386 ms 21216 KB Output is correct
8 Correct 361 ms 21232 KB Output is correct
9 Correct 356 ms 21220 KB Output is correct
10 Correct 377 ms 21212 KB Output is correct
11 Correct 385 ms 23084 KB Output is correct
12 Correct 390 ms 23300 KB Output is correct
13 Correct 397 ms 23252 KB Output is correct
14 Correct 373 ms 22452 KB Output is correct

Subtask #3
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 50 ms 3116 KB Output is correct
2 Correct 41 ms 6116 KB Output is correct
3 Correct 62 ms 8976 KB Output is correct
4 Correct 213 ms 27512 KB Output is correct
5 Correct 227 ms 27552 KB Output is correct
6 Correct 359 ms 27192 KB Output is correct
7 Correct 229 ms 27552 KB Output is correct
8 Correct 210 ms 27192 KB Output is correct
9 Correct 229 ms 27488 KB Output is correct

Subtask #4
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 540 KB Output is correct
2 Correct 27 ms 2632 KB Output is correct
3 Correct 286 ms 16508 KB Output is correct
4 Correct 355 ms 21220 KB Output is correct
5 Correct 348 ms 21232 KB Output is correct
6 Correct 346 ms 21216 KB Output is correct
7 Correct 373 ms 21216 KB Output is correct
8 Correct 350 ms 21200 KB Output is correct
9 Correct 372 ms 21224 KB Output is correct
10 Correct 382 ms 21212 KB Output is correct
11 Correct 388 ms 21872 KB Output is correct
12 Correct 551 ms 22328 KB Output is correct
13 Correct 374 ms 22444 KB Output is correct
14 Correct 387 ms 23008 KB Output is correct
15 Correct 347 ms 21212 KB Output is correct
16 Correct 361 ms 21208 KB Output is correct
17 Correct 382 ms 23204 KB Output is correct
18 Correct 443 ms 23120 KB Output is correct
19 Correct 347 ms 21228 KB Output is correct
20 Correct 386 ms 23120 KB Output is correct
21 Correct 399 ms 21400 KB Output is correct
22 Correct 393 ms 21396 KB Output is correct
23 Correct 325 ms 21464 KB Output is correct
24 Correct 369 ms 22120 KB Output is correct
25 Correct 408 ms 28176 KB Output is correct

Subtask #5
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 38 ms 2976 KB Output is correct
2 Correct 35 ms 3236 KB Output is correct
3 Correct 457 ms 24552 KB Output is correct
4 Correct 454 ms 27136 KB Output is correct
5 Correct 582 ms 31760 KB Output is correct
6 Correct 627 ms 31728 KB Output is correct
7 Correct 753 ms 31548 KB Output is correct
8 Correct 723 ms 31728 KB Output is correct
9 Correct 532 ms 24300 KB Output is correct
10 Correct 554 ms 24752 KB Output is correct
11 Correct 546 ms 25340 KB Output is correct
12 Correct 715 ms 30736 KB Output is correct
13 Correct 550 ms 31212 KB Output is correct
14 Correct 590 ms 33068 KB Output is correct
15 Correct 557 ms 33036 KB Output is correct
16 Correct 613 ms 28328 KB Output is correct
17 Correct 392 ms 21460 KB Output is correct
18 Correct 400 ms 21712 KB Output is correct
19 Correct 389 ms 21824 KB Output is correct
20 Correct 389 ms 21788 KB Output is correct
21 Correct 542 ms 31140 KB Output is correct

Subtask #6
21.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 30 ms 2984 KB Output is correct
2 Correct 65 ms 3240 KB Output is correct
3 Correct 427 ms 24808 KB Output is correct
4 Correct 532 ms 25880 KB Output is correct
5 Correct 487 ms 27176 KB Output is correct
6 Correct 585 ms 31712 KB Output is correct
7 Correct 486 ms 24828 KB Output is correct
8 Correct 466 ms 25844 KB Output is correct
9 Correct 637 ms 27120 KB Output is correct
10 Correct 579 ms 31744 KB Output is correct
11 Correct 554 ms 31752 KB Output is correct
12 Correct 634 ms 31720 KB Output is correct
13 Correct 494 ms 25328 KB Output is correct
14 Correct 511 ms 24812 KB Output is correct
15 Correct 532 ms 25232 KB Output is correct
16 Correct 563 ms 24708 KB Output is correct
17 Correct 543 ms 25332 KB Output is correct
18 Correct 562 ms 24680 KB Output is correct
19 Correct 629 ms 31472 KB Output is correct
20 Correct 538 ms 32252 KB Output is correct
21 Correct 567 ms 33220 KB Output is correct
22 Correct 732 ms 33208 KB Output is correct
23 Correct 608 ms 33092 KB Output is correct
24 Correct 562 ms 33260 KB Output is correct
25 Correct 591 ms 33284 KB Output is correct
26 Correct 595 ms 33036 KB Output is correct
27 Correct 388 ms 21704 KB Output is correct
28 Correct 383 ms 21648 KB Output is correct
29 Partially correct 377 ms 21868 KB Output is partially correct
30 Partially correct 423 ms 21936 KB Output is partially correct
31 Correct 539 ms 21640 KB Output is correct
32 Partially correct 487 ms 21592 KB Output is partially correct
33 Correct 393 ms 21964 KB Output is correct
34 Correct 374 ms 21716 KB Output is correct
35 Correct 390 ms 21596 KB Output is correct
36 Correct 482 ms 21580 KB Output is correct
37 Correct 342 ms 21980 KB Output is correct
38 Correct 431 ms 22304 KB Output is correct
39 Correct 535 ms 31076 KB Output is correct
40 Correct 530 ms 31304 KB Output is correct
41 Correct 530 ms 30440 KB Output is correct
42 Correct 539 ms 30488 KB Output is correct