oj.uz

Submission #75062

# Submission time Handle Problem Language Result Execution time Memory
75062 2018-09-08T08:12:28 Z dacin21 Highway Tolls (IOI18_highway) C++14
90 / 100
 692 ms 33304 KB 
#include "highway.h"



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


mt19937 rng(931621953);
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 376 KB Output is correct
2 Correct 2 ms 248 KB Output is correct
3 Correct 3 ms 340 KB Output is correct
4 Correct 2 ms 420 KB Output is correct
5 Correct 2 ms 420 KB Output is correct
6 Correct 2 ms 416 KB Output is correct
7 Correct 2 ms 328 KB Output is correct
8 Correct 3 ms 344 KB Output is correct
9 Correct 3 ms 376 KB Output is correct
10 Correct 2 ms 456 KB Output is correct
11 Correct 2 ms 248 KB Output is correct
12 Correct 3 ms 376 KB Output is correct

Subtask #2
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 540 KB Output is correct
2 Correct 33 ms 2632 KB Output is correct
3 Correct 397 ms 21208 KB Output is correct
4 Correct 385 ms 21208 KB Output is correct
5 Correct 414 ms 21208 KB Output is correct
6 Correct 366 ms 21216 KB Output is correct
7 Correct 367 ms 21228 KB Output is correct
8 Correct 359 ms 21216 KB Output is correct
9 Correct 397 ms 21236 KB Output is correct
10 Correct 369 ms 21212 KB Output is correct
11 Correct 369 ms 22580 KB Output is correct
12 Correct 399 ms 23604 KB Output is correct
13 Correct 389 ms 23288 KB Output is correct
14 Correct 369 ms 22916 KB Output is correct

Subtask #3
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 19 ms 3288 KB Output is correct
2 Correct 47 ms 6488 KB Output is correct
3 Correct 65 ms 8536 KB Output is correct
4 Correct 232 ms 28416 KB Output is correct
5 Correct 211 ms 28400 KB Output is correct
6 Correct 207 ms 28064 KB Output is correct
7 Correct 218 ms 28328 KB Output is correct
8 Correct 225 ms 28076 KB Output is correct
9 Correct 367 ms 28324 KB Output is correct

Subtask #4
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 536 KB Output is correct
2 Correct 50 ms 2632 KB Output is correct
3 Correct 303 ms 16508 KB Output is correct
4 Correct 363 ms 21228 KB Output is correct
5 Correct 421 ms 21220 KB Output is correct
6 Correct 358 ms 21228 KB Output is correct
7 Correct 350 ms 21216 KB Output is correct
8 Correct 363 ms 21200 KB Output is correct
9 Correct 348 ms 21220 KB Output is correct
10 Correct 392 ms 21216 KB Output is correct
11 Correct 367 ms 22512 KB Output is correct
12 Correct 364 ms 22684 KB Output is correct
13 Correct 479 ms 23628 KB Output is correct
14 Correct 383 ms 22936 KB Output is correct
15 Correct 352 ms 21208 KB Output is correct
16 Correct 356 ms 21212 KB Output is correct
17 Correct 482 ms 22452 KB Output is correct
18 Correct 512 ms 22588 KB Output is correct
19 Correct 337 ms 21216 KB Output is correct
20 Correct 356 ms 23480 KB Output is correct
21 Correct 357 ms 21392 KB Output is correct
22 Correct 464 ms 21400 KB Output is correct
23 Correct 347 ms 21456 KB Output is correct
24 Correct 335 ms 22132 KB Output is correct
25 Correct 409 ms 26580 KB Output is correct

Subtask #5
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 44 ms 2980 KB Output is correct
2 Correct 35 ms 3244 KB Output is correct
3 Correct 442 ms 24544 KB Output is correct
4 Correct 481 ms 27124 KB Output is correct
5 Correct 590 ms 31732 KB Output is correct
6 Correct 643 ms 31752 KB Output is correct
7 Correct 601 ms 31556 KB Output is correct
8 Correct 619 ms 31736 KB Output is correct
9 Correct 496 ms 24200 KB Output is correct
10 Correct 490 ms 24848 KB Output is correct
11 Correct 566 ms 25344 KB Output is correct
12 Correct 539 ms 30696 KB Output is correct
13 Correct 662 ms 31216 KB Output is correct
14 Correct 594 ms 33084 KB Output is correct
15 Correct 582 ms 33080 KB Output is correct
16 Correct 528 ms 28340 KB Output is correct
17 Correct 342 ms 21468 KB Output is correct
18 Correct 394 ms 21720 KB Output is correct
19 Correct 412 ms 21720 KB Output is correct
20 Correct 507 ms 21788 KB Output is correct
21 Correct 676 ms 30356 KB Output is correct

Subtask #6
21.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 32 ms 2984 KB Output is correct
2 Correct 67 ms 3228 KB Output is correct
3 Correct 456 ms 24844 KB Output is correct
4 Correct 412 ms 25860 KB Output is correct
5 Correct 495 ms 27100 KB Output is correct
6 Correct 561 ms 31708 KB Output is correct
7 Correct 438 ms 24844 KB Output is correct
8 Correct 426 ms 25896 KB Output is correct
9 Correct 485 ms 27136 KB Output is correct
10 Correct 551 ms 31732 KB Output is correct
11 Correct 692 ms 31704 KB Output is correct
12 Correct 625 ms 31740 KB Output is correct
13 Correct 558 ms 25328 KB Output is correct
14 Correct 488 ms 24784 KB Output is correct
15 Correct 577 ms 25276 KB Output is correct
16 Correct 599 ms 24708 KB Output is correct
17 Correct 536 ms 25344 KB Output is correct
18 Correct 530 ms 24720 KB Output is correct
19 Correct 640 ms 31412 KB Output is correct
20 Correct 574 ms 32304 KB Output is correct
21 Correct 603 ms 33224 KB Output is correct
22 Correct 554 ms 33216 KB Output is correct
23 Correct 582 ms 33064 KB Output is correct
24 Correct 594 ms 33244 KB Output is correct
25 Correct 584 ms 33304 KB Output is correct
26 Correct 576 ms 33040 KB Output is correct
27 Correct 381 ms 21708 KB Output is correct
28 Correct 381 ms 21648 KB Output is correct
29 Partially correct 390 ms 21868 KB Output is partially correct
30 Correct 503 ms 21924 KB Output is correct
31 Correct 402 ms 21652 KB Output is correct
32 Correct 458 ms 21584 KB Output is correct
33 Correct 403 ms 21956 KB Output is correct
34 Correct 513 ms 21720 KB Output is correct
35 Correct 360 ms 21604 KB Output is correct
36 Correct 525 ms 21576 KB Output is correct
37 Correct 399 ms 21996 KB Output is correct
38 Correct 415 ms 22292 KB Output is correct
39 Correct 527 ms 31008 KB Output is correct
40 Correct 549 ms 30192 KB Output is correct
41 Correct 556 ms 30136 KB Output is correct
42 Correct 604 ms 30396 KB Output is correct