oj.uz

Submission #75061

# Submission time Handle Problem Language Result Execution time Memory
75061 2018-09-08T08:09:42 Z dacin21 Highway Tolls (IOI18_highway) C++14
90 / 100
 740 ms 33276 KB 
#include "highway.h"



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


mt19937 rng(5132495);
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 2 ms 344 KB Output is correct
2 Correct 2 ms 344 KB Output is correct
3 Correct 3 ms 248 KB Output is correct
4 Correct 2 ms 376 KB Output is correct
5 Correct 2 ms 332 KB Output is correct
6 Correct 2 ms 340 KB Output is correct
7 Correct 2 ms 416 KB Output is correct
8 Correct 2 ms 344 KB Output is correct
9 Correct 2 ms 340 KB Output is correct
10 Correct 2 ms 376 KB Output is correct
11 Correct 2 ms 376 KB Output is correct
12 Correct 2 ms 328 KB Output is correct

Subtask #2
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 552 KB Output is correct
2 Correct 31 ms 2640 KB Output is correct
3 Correct 411 ms 21212 KB Output is correct
4 Correct 510 ms 21220 KB Output is correct
5 Correct 367 ms 21208 KB Output is correct
6 Correct 508 ms 21228 KB Output is correct
7 Correct 383 ms 21216 KB Output is correct
8 Correct 386 ms 21212 KB Output is correct
9 Correct 496 ms 21216 KB Output is correct
10 Correct 400 ms 21212 KB Output is correct
11 Correct 416 ms 23228 KB Output is correct
12 Correct 394 ms 23868 KB Output is correct
13 Correct 383 ms 22628 KB Output is correct
14 Correct 383 ms 22440 KB Output is correct

Subtask #3
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 43 ms 3204 KB Output is correct
2 Correct 39 ms 6404 KB Output is correct
3 Correct 60 ms 9124 KB Output is correct
4 Correct 272 ms 28360 KB Output is correct
5 Correct 233 ms 28280 KB Output is correct
6 Correct 206 ms 28008 KB Output is correct
7 Correct 216 ms 28268 KB Output is correct
8 Correct 214 ms 28008 KB Output is correct
9 Correct 227 ms 28264 KB Output is correct

Subtask #4
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 536 KB Output is correct
2 Correct 30 ms 2592 KB Output is correct
3 Correct 315 ms 16504 KB Output is correct
4 Correct 375 ms 21220 KB Output is correct
5 Correct 358 ms 21224 KB Output is correct
6 Correct 422 ms 21220 KB Output is correct
7 Correct 357 ms 21208 KB Output is correct
8 Correct 348 ms 21196 KB Output is correct
9 Correct 432 ms 21220 KB Output is correct
10 Correct 381 ms 21220 KB Output is correct
11 Correct 431 ms 21856 KB Output is correct
12 Correct 374 ms 22508 KB Output is correct
13 Correct 474 ms 23028 KB Output is correct
14 Correct 358 ms 22396 KB Output is correct
15 Correct 339 ms 21212 KB Output is correct
16 Correct 343 ms 21212 KB Output is correct
17 Correct 488 ms 22648 KB Output is correct
18 Correct 376 ms 22164 KB Output is correct
19 Correct 351 ms 21232 KB Output is correct
20 Correct 371 ms 24280 KB Output is correct
21 Correct 359 ms 21392 KB Output is correct
22 Correct 367 ms 21412 KB Output is correct
23 Correct 326 ms 21460 KB Output is correct
24 Correct 345 ms 22112 KB Output is correct
25 Correct 434 ms 28268 KB Output is correct

Subtask #5
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 29 ms 2976 KB Output is correct
2 Correct 37 ms 3244 KB Output is correct
3 Correct 421 ms 24536 KB Output is correct
4 Correct 497 ms 27128 KB Output is correct
5 Correct 557 ms 31712 KB Output is correct
6 Correct 659 ms 31748 KB Output is correct
7 Correct 564 ms 31572 KB Output is correct
8 Correct 558 ms 31716 KB Output is correct
9 Correct 520 ms 24252 KB Output is correct
10 Correct 568 ms 24784 KB Output is correct
11 Correct 704 ms 25316 KB Output is correct
12 Correct 525 ms 30696 KB Output is correct
13 Correct 559 ms 31232 KB Output is correct
14 Correct 610 ms 33100 KB Output is correct
15 Correct 563 ms 33124 KB Output is correct
16 Correct 588 ms 28344 KB Output is correct
17 Correct 524 ms 21464 KB Output is correct
18 Correct 367 ms 21736 KB Output is correct
19 Correct 511 ms 21700 KB Output is correct
20 Correct 406 ms 21808 KB Output is correct
21 Correct 558 ms 30080 KB Output is correct

Subtask #6
21.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 43 ms 3004 KB Output is correct
2 Correct 36 ms 3236 KB Output is correct
3 Correct 428 ms 24824 KB Output is correct
4 Correct 479 ms 25888 KB Output is correct
5 Correct 609 ms 27108 KB Output is correct
6 Correct 579 ms 31700 KB Output is correct
7 Correct 438 ms 24844 KB Output is correct
8 Correct 433 ms 25920 KB Output is correct
9 Correct 508 ms 27156 KB Output is correct
10 Correct 740 ms 31708 KB Output is correct
11 Correct 567 ms 31748 KB Output is correct
12 Correct 600 ms 31704 KB Output is correct
13 Correct 512 ms 25352 KB Output is correct
14 Correct 496 ms 24784 KB Output is correct
15 Correct 565 ms 25224 KB Output is correct
16 Correct 486 ms 24796 KB Output is correct
17 Correct 558 ms 25336 KB Output is correct
18 Correct 562 ms 24692 KB Output is correct
19 Correct 539 ms 31424 KB Output is correct
20 Correct 548 ms 32320 KB Output is correct
21 Correct 589 ms 33260 KB Output is correct
22 Correct 584 ms 33236 KB Output is correct
23 Correct 560 ms 33092 KB Output is correct
24 Correct 582 ms 33276 KB Output is correct
25 Correct 581 ms 33232 KB Output is correct
26 Correct 598 ms 33108 KB Output is correct
27 Partially correct 375 ms 21704 KB Output is partially correct
28 Correct 345 ms 21648 KB Output is correct
29 Correct 373 ms 21864 KB Output is correct
30 Correct 402 ms 21940 KB Output is correct
31 Correct 381 ms 21652 KB Output is correct
32 Correct 397 ms 21600 KB Output is correct
33 Correct 396 ms 21964 KB Output is correct
34 Correct 479 ms 21736 KB Output is correct
35 Correct 481 ms 21600 KB Output is correct
36 Partially correct 376 ms 21576 KB Output is partially correct
37 Correct 377 ms 21976 KB Output is correct
38 Correct 434 ms 22300 KB Output is correct
39 Correct 585 ms 30888 KB Output is correct
40 Correct 537 ms 30756 KB Output is correct
41 Correct 521 ms 30428 KB Output is correct
42 Correct 614 ms 30896 KB Output is correct