oj.uz

Submission #75066

# Submission time Handle Problem Language Result Execution time Memory
75066 2018-09-08T08:23:05 Z dacin21 Highway Tolls (IOI18_highway) C++14
90 / 100
 723 ms 33320 KB 
#include "highway.h"



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


mt19937 rng(59456231);
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 336 KB Output is correct
2 Correct 3 ms 376 KB Output is correct
3 Correct 3 ms 340 KB Output is correct
4 Correct 2 ms 376 KB Output is correct
5 Correct 3 ms 248 KB Output is correct
6 Correct 3 ms 340 KB Output is correct
7 Correct 3 ms 332 KB Output is correct
8 Correct 2 ms 376 KB Output is correct
9 Correct 2 ms 416 KB Output is correct
10 Correct 2 ms 296 KB Output is correct
11 Correct 2 ms 344 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 504 KB Output is correct
2 Correct 27 ms 2632 KB Output is correct
3 Correct 352 ms 21208 KB Output is correct
4 Correct 396 ms 21220 KB Output is correct
5 Correct 390 ms 21232 KB Output is correct
6 Correct 495 ms 21228 KB Output is correct
7 Correct 366 ms 21220 KB Output is correct
8 Correct 378 ms 21232 KB Output is correct
9 Correct 362 ms 21216 KB Output is correct
10 Correct 409 ms 21228 KB Output is correct
11 Correct 363 ms 23160 KB Output is correct
12 Correct 353 ms 23592 KB Output is correct
13 Correct 386 ms 22544 KB Output is correct
14 Correct 376 ms 22388 KB Output is correct

Subtask #3
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 18 ms 3260 KB Output is correct
2 Correct 90 ms 6688 KB Output is correct
3 Correct 58 ms 9592 KB Output is correct
4 Correct 215 ms 28700 KB Output is correct
5 Correct 359 ms 28620 KB Output is correct
6 Correct 234 ms 28372 KB Output is correct
7 Correct 231 ms 28736 KB Output is correct
8 Correct 222 ms 28360 KB Output is correct
9 Correct 228 ms 28616 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 34 ms 2632 KB Output is correct
3 Correct 237 ms 16516 KB Output is correct
4 Correct 319 ms 21232 KB Output is correct
5 Correct 346 ms 21212 KB Output is correct
6 Correct 339 ms 21216 KB Output is correct
7 Correct 351 ms 21216 KB Output is correct
8 Correct 345 ms 21184 KB Output is correct
9 Correct 373 ms 21216 KB Output is correct
10 Correct 362 ms 21216 KB Output is correct
11 Correct 360 ms 22236 KB Output is correct
12 Correct 352 ms 22580 KB Output is correct
13 Correct 501 ms 23028 KB Output is correct
14 Correct 358 ms 23356 KB Output is correct
15 Correct 361 ms 21216 KB Output is correct
16 Correct 472 ms 20876 KB Output is correct
17 Correct 485 ms 22432 KB Output is correct
18 Correct 372 ms 22836 KB Output is correct
19 Correct 345 ms 21224 KB Output is correct
20 Correct 419 ms 23280 KB Output is correct
21 Correct 356 ms 21396 KB Output is correct
22 Correct 410 ms 21392 KB Output is correct
23 Correct 457 ms 21456 KB Output is correct
24 Correct 336 ms 22120 KB Output is correct
25 Correct 404 ms 26520 KB Output is correct

Subtask #5
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 28 ms 2976 KB Output is correct
2 Correct 38 ms 3240 KB Output is correct
3 Correct 563 ms 24548 KB Output is correct
4 Correct 488 ms 27152 KB Output is correct
5 Correct 580 ms 31772 KB Output is correct
6 Correct 532 ms 31736 KB Output is correct
7 Correct 548 ms 31576 KB Output is correct
8 Correct 723 ms 31700 KB Output is correct
9 Correct 513 ms 24332 KB Output is correct
10 Correct 520 ms 24740 KB Output is correct
11 Correct 551 ms 25320 KB Output is correct
12 Correct 566 ms 30744 KB Output is correct
13 Correct 553 ms 31220 KB Output is correct
14 Correct 582 ms 33104 KB Output is correct
15 Correct 518 ms 33120 KB Output is correct
16 Correct 575 ms 28312 KB Output is correct
17 Correct 387 ms 21480 KB Output is correct
18 Correct 374 ms 21736 KB Output is correct
19 Correct 390 ms 21712 KB Output is correct
20 Correct 393 ms 21796 KB Output is correct
21 Correct 515 ms 30796 KB Output is correct

Subtask #6
21.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 34 ms 2976 KB Output is correct
2 Correct 40 ms 3236 KB Output is correct
3 Correct 447 ms 24832 KB Output is correct
4 Correct 451 ms 25908 KB Output is correct
5 Correct 471 ms 27124 KB Output is correct
6 Correct 607 ms 31704 KB Output is correct
7 Correct 432 ms 24824 KB Output is correct
8 Correct 431 ms 25888 KB Output is correct
9 Correct 476 ms 27144 KB Output is correct
10 Correct 581 ms 31720 KB Output is correct
11 Correct 580 ms 31716 KB Output is correct
12 Correct 580 ms 31676 KB Output is correct
13 Correct 530 ms 25356 KB Output is correct
14 Correct 506 ms 24788 KB Output is correct
15 Correct 565 ms 25256 KB Output is correct
16 Correct 569 ms 24696 KB Output is correct
17 Correct 563 ms 25328 KB Output is correct
18 Correct 643 ms 24680 KB Output is correct
19 Correct 703 ms 31440 KB Output is correct
20 Correct 531 ms 32304 KB Output is correct
21 Correct 578 ms 33264 KB Output is correct
22 Correct 568 ms 33216 KB Output is correct
23 Correct 557 ms 33108 KB Output is correct
24 Correct 717 ms 33288 KB Output is correct
25 Correct 620 ms 33320 KB Output is correct
26 Correct 566 ms 33112 KB Output is correct
27 Correct 436 ms 21704 KB Output is correct
28 Correct 375 ms 21640 KB Output is correct
29 Correct 387 ms 21852 KB Output is correct
30 Partially correct 394 ms 21920 KB Output is partially correct
31 Correct 407 ms 21656 KB Output is correct
32 Correct 374 ms 21600 KB Output is correct
33 Correct 381 ms 21960 KB Output is correct
34 Correct 364 ms 21736 KB Output is correct
35 Correct 381 ms 21596 KB Output is correct
36 Correct 483 ms 21564 KB Output is correct
37 Correct 478 ms 21980 KB Output is correct
38 Correct 422 ms 22288 KB Output is correct
39 Correct 555 ms 31472 KB Output is correct
40 Correct 533 ms 30304 KB Output is correct
41 Correct 650 ms 30508 KB Output is correct
42 Correct 563 ms 30140 KB Output is correct