oj.uz

Submission #75065

# Submission time Handle Problem Language Result Execution time Memory
75065 2018-09-08T08:19:41 Z dacin21 Highway Tolls (IOI18_highway) C++14
90 / 100
 774 ms 33304 KB 
#include "highway.h"



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


mt19937 rng(127345093);
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 276 KB Output is correct
3 Correct 2 ms 344 KB Output is correct
4 Correct 2 ms 460 KB Output is correct
5 Correct 2 ms 336 KB Output is correct
6 Correct 3 ms 376 KB Output is correct
7 Correct 2 ms 376 KB Output is correct
8 Correct 2 ms 416 KB Output is correct
9 Correct 2 ms 416 KB Output is correct
10 Correct 2 ms 248 KB Output is correct
11 Correct 2 ms 416 KB Output is correct
12 Correct 2 ms 416 KB Output is correct

Subtask #2
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 460 KB Output is correct
2 Correct 30 ms 2632 KB Output is correct
3 Correct 386 ms 21232 KB Output is correct
4 Correct 347 ms 21220 KB Output is correct
5 Correct 401 ms 21208 KB Output is correct
6 Correct 366 ms 21216 KB Output is correct
7 Correct 385 ms 21244 KB Output is correct
8 Correct 384 ms 21224 KB Output is correct
9 Correct 374 ms 21216 KB Output is correct
10 Correct 366 ms 21220 KB Output is correct
11 Correct 378 ms 22584 KB Output is correct
12 Correct 372 ms 23536 KB Output is correct
13 Correct 395 ms 22800 KB Output is correct
14 Correct 367 ms 23028 KB Output is correct

Subtask #3
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 3468 KB Output is correct
2 Correct 40 ms 6004 KB Output is correct
3 Correct 68 ms 8580 KB Output is correct
4 Correct 230 ms 25260 KB Output is correct
5 Correct 392 ms 25240 KB Output is correct
6 Correct 352 ms 24928 KB Output is correct
7 Correct 219 ms 25188 KB Output is correct
8 Correct 352 ms 24932 KB Output is correct
9 Correct 358 ms 25256 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 31 ms 2620 KB Output is correct
3 Correct 245 ms 16576 KB Output is correct
4 Correct 354 ms 21208 KB Output is correct
5 Correct 370 ms 21212 KB Output is correct
6 Correct 373 ms 21208 KB Output is correct
7 Correct 361 ms 21208 KB Output is correct
8 Correct 496 ms 21192 KB Output is correct
9 Correct 346 ms 21232 KB Output is correct
10 Correct 412 ms 21212 KB Output is correct
11 Correct 351 ms 22292 KB Output is correct
12 Correct 425 ms 23856 KB Output is correct
13 Correct 503 ms 23124 KB Output is correct
14 Correct 385 ms 22832 KB Output is correct
15 Correct 349 ms 21224 KB Output is correct
16 Correct 340 ms 20864 KB Output is correct
17 Correct 409 ms 22436 KB Output is correct
18 Correct 390 ms 22568 KB Output is correct
19 Correct 335 ms 21216 KB Output is correct
20 Correct 390 ms 22944 KB Output is correct
21 Correct 366 ms 21396 KB Output is correct
22 Correct 384 ms 21396 KB Output is correct
23 Correct 414 ms 21476 KB Output is correct
24 Correct 358 ms 22112 KB Output is correct
25 Correct 432 ms 25620 KB Output is correct

Subtask #5
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 34 ms 2988 KB Output is correct
2 Correct 39 ms 3240 KB Output is correct
3 Correct 424 ms 24536 KB Output is correct
4 Correct 490 ms 27108 KB Output is correct
5 Correct 748 ms 31728 KB Output is correct
6 Correct 544 ms 31728 KB Output is correct
7 Correct 580 ms 31532 KB Output is correct
8 Correct 530 ms 31728 KB Output is correct
9 Correct 501 ms 24328 KB Output is correct
10 Correct 574 ms 24756 KB Output is correct
11 Correct 530 ms 25308 KB Output is correct
12 Correct 705 ms 30752 KB Output is correct
13 Correct 548 ms 31252 KB Output is correct
14 Correct 737 ms 33064 KB Output is correct
15 Correct 550 ms 33092 KB Output is correct
16 Correct 694 ms 28368 KB Output is correct
17 Correct 498 ms 21456 KB Output is correct
18 Correct 515 ms 21716 KB Output is correct
19 Correct 399 ms 21712 KB Output is correct
20 Correct 433 ms 21788 KB Output is correct
21 Correct 571 ms 31032 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 30 ms 3240 KB Output is correct
3 Correct 442 ms 24848 KB Output is correct
4 Correct 471 ms 25856 KB Output is correct
5 Correct 481 ms 27184 KB Output is correct
6 Correct 694 ms 31696 KB Output is correct
7 Correct 563 ms 24820 KB Output is correct
8 Correct 457 ms 25900 KB Output is correct
9 Correct 494 ms 27156 KB Output is correct
10 Correct 711 ms 31756 KB Output is correct
11 Correct 546 ms 31776 KB Output is correct
12 Correct 591 ms 31728 KB Output is correct
13 Correct 686 ms 25332 KB Output is correct
14 Correct 601 ms 24784 KB Output is correct
15 Correct 596 ms 25280 KB Output is correct
16 Correct 720 ms 24712 KB Output is correct
17 Correct 537 ms 25336 KB Output is correct
18 Correct 553 ms 24688 KB Output is correct
19 Correct 583 ms 31428 KB Output is correct
20 Correct 563 ms 32336 KB Output is correct
21 Correct 590 ms 33276 KB Output is correct
22 Correct 589 ms 33220 KB Output is correct
23 Correct 750 ms 33092 KB Output is correct
24 Correct 533 ms 33304 KB Output is correct
25 Correct 657 ms 33252 KB Output is correct
26 Correct 594 ms 33044 KB Output is correct
27 Correct 405 ms 21704 KB Output is correct
28 Correct 358 ms 21644 KB Output is correct
29 Correct 447 ms 21860 KB Output is correct
30 Correct 407 ms 21924 KB Output is correct
31 Correct 384 ms 21656 KB Output is correct
32 Partially correct 502 ms 21584 KB Output is partially correct
33 Correct 415 ms 21960 KB Output is correct
34 Correct 385 ms 21728 KB Output is correct
35 Correct 418 ms 21596 KB Output is correct
36 Partially correct 338 ms 21580 KB Output is partially correct
37 Partially correct 411 ms 21980 KB Output is partially correct
38 Correct 434 ms 22296 KB Output is correct
39 Correct 560 ms 30976 KB Output is correct
40 Correct 774 ms 30104 KB Output is correct
41 Correct 521 ms 30036 KB Output is correct
42 Correct 607 ms 31228 KB Output is correct