結果

問題 No.2319 Friends+
ユーザー hliuser1hliuser1
提出日時 2023-12-26 06:17:02
言語 C++23
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 2,776 ms / 3,000 ms
コード長 3,657 bytes
コンパイル時間 5,851 ms
コンパイル使用メモリ 309,476 KB
実行使用メモリ 71,984 KB
最終ジャッジ日時 2024-09-27 14:58:55
合計ジャッジ時間 34,585 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge5
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 19 ms
56,936 KB
testcase_01 AC 20 ms
57,052 KB
testcase_02 AC 908 ms
69,296 KB
testcase_03 AC 821 ms
69,472 KB
testcase_04 AC 685 ms
69,348 KB
testcase_05 AC 797 ms
69,220 KB
testcase_06 AC 652 ms
69,220 KB
testcase_07 AC 919 ms
71,700 KB
testcase_08 AC 914 ms
71,604 KB
testcase_09 AC 918 ms
71,700 KB
testcase_10 AC 926 ms
71,728 KB
testcase_11 AC 930 ms
71,652 KB
testcase_12 AC 19 ms
57,068 KB
testcase_13 AC 20 ms
57,192 KB
testcase_14 AC 20 ms
57,196 KB
testcase_15 AC 20 ms
57,188 KB
testcase_16 AC 20 ms
57,136 KB
testcase_17 AC 19 ms
57,056 KB
testcase_18 AC 237 ms
58,984 KB
testcase_19 AC 671 ms
71,680 KB
testcase_20 AC 457 ms
68,836 KB
testcase_21 AC 404 ms
65,504 KB
testcase_22 AC 492 ms
69,940 KB
testcase_23 AC 598 ms
71,296 KB
testcase_24 AC 615 ms
71,140 KB
testcase_25 AC 586 ms
71,784 KB
testcase_26 AC 581 ms
71,404 KB
testcase_27 AC 570 ms
70,884 KB
testcase_28 AC 545 ms
70,760 KB
testcase_29 AC 514 ms
70,636 KB
testcase_30 AC 486 ms
69,604 KB
testcase_31 AC 449 ms
68,200 KB
testcase_32 AC 388 ms
64,868 KB
testcase_33 AC 332 ms
63,972 KB
testcase_34 AC 267 ms
60,644 KB
testcase_35 AC 246 ms
58,808 KB
testcase_36 AC 317 ms
71,984 KB
testcase_37 AC 1,587 ms
63,592 KB
testcase_38 AC 199 ms
58,936 KB
testcase_39 AC 176 ms
58,728 KB
testcase_40 AC 178 ms
58,852 KB
testcase_41 AC 175 ms
58,732 KB
testcase_42 AC 197 ms
58,856 KB
testcase_43 AC 260 ms
59,116 KB
testcase_44 AC 494 ms
60,204 KB
testcase_45 AC 1,588 ms
64,996 KB
testcase_46 AC 2,776 ms
70,756 KB
権限があれば一括ダウンロードができます

ソースコード

diff # 

// https://yukicoder.me/problems/no/2319
// really cool problem
//
// Solution 0. use bitsets and bruteforce (cheating)
//
// Solution 1. sqrt over nodes
// let K = sqrt(M)
// a person is "few" if it has < K friends and "many" if >= K
// there are at most 2M / K ~= K people that are "many"
// to solve a query where x is few, brute force it
// to solve a query where x is many, consider its friends that are:
//     a. many - you can check ALL many's for the condition
//     b. few  - store this as map f[i][j] = # of few friends of the many i in world j
// update naively, it works in O(Q*sqrt M + N*sqrt M + M)
//
// Solution 2. ft. Jerry -> sqrt over queries
// for each chunk, recompute a map of for each person i, how many friends they have in world j
// then for each query, loop over the previous queries in the chunk and simulate. if by the end,
// you still have at least one friend in world[y], ur good
// the map computations take M sqrt(Q) time total, the rest is Q sqrt(Q)
#include <bits/stdc++.h>
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2")
using namespace std;

#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template <typename K, typename V>
using HashTable = gp_hash_table<K,V>;

constexpr size_t MXN = 20001;
constexpr size_t MXM = 400000;
constexpr size_t SQR = 450;

#define all(x) begin(x), end(x)

signed main() {
    cin.tie(0)->sync_with_stdio(0);
    int N, M, Q;
    cin >> N >> M;

    short world[MXN];
    bitset<MXN> friends[MXN];
    vector<short> friendss[MXN];
    short friendships[MXM];
    HashTable<int, short> initial_count[MXN];
    // initial_count[i][j] = # of friends of i in world j
    short X[SQR], Y[SQR];

    vector<int> whos_involved;

    for (int i = 1; i <= N; ++i)
        cin >> world[i];

    for (int i = 0; i < M; ++i) {
        short a, b;
        cin >> a >> b;
        friendss[a].push_back(b);
        friendss[b].push_back(a);
        friendships[2*i] = a, friendships[2*i+1] = b;
        friends[a][b] = true;
        friends[b][a] = true;
    }

    auto reset_map = [&] {
        sort( all(whos_involved) );
        whos_involved.resize(unique(all(whos_involved)) - begin(whos_involved));

        for (int c : whos_involved) {
            if (!initial_count[c].empty())
                initial_count[c].clear();
            for (int f : friendss[c]) {
                ++initial_count[c][world[f]];
            }
        }
    };

    cin >> Q;
    int K = sqrt(Q);
    int q = 0;
    HashTable<int,vector<int>> succeeded_wx, succeeded_wy;

    while (q < Q) {
        int last = min(Q, q + K);
        for (int k = q; k < last; ++k) {
            cin >> X[k-q] >> Y[k-q];
            whos_involved.push_back(X[k-q]);
            whos_involved.push_back(Y[k-q]);
        }
        reset_map();
        for (int k = 0; k < K && q < Q; ++k, ++q) {
            short x = X[k], y = Y[k];
            if (world[x] == world[y]) {
                cout << "No\n";
                continue;
            }

            int start = initial_count[x][world[y]];
            for (int xl : succeeded_wx[ world[y] ]) {
                start -= (friends[x][xl]);
            }
            for (int xl : succeeded_wy[ world[y] ]) {
                start += (friends[x][xl]);
            }
            if (start > 0) {
                cout << "Yes\n";
                succeeded_wx[world[x]].push_back(x);
                succeeded_wy[world[y]].push_back(x);
                world[x] = world[y];
            }
            else cout << "No\n";
        }
        succeeded_wx.clear();
        succeeded_wy.clear();
        whos_involved.clear();
    }
    return 0;
}
0