結果

問題 No.2316 Freight Train
ユーザー erbowlerbowl
提出日時 2023-05-26 21:26:38
言語 C++17
(gcc 12.3.0 + boost 1.83.0)
結果
AC  
実行時間 493 ms / 2,000 ms
コード長 8,278 bytes
コンパイル時間 2,180 ms
コンパイル使用メモリ 205,120 KB
実行使用メモリ 6,944 KB
最終ジャッジ日時 2024-06-07 05:24:27
合計ジャッジ時間 14,746 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge4
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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 2 ms
6,816 KB
testcase_01 AC 2 ms
6,944 KB
testcase_02 AC 2 ms
6,940 KB
testcase_03 AC 468 ms
6,940 KB
testcase_04 AC 251 ms
6,940 KB
testcase_05 AC 178 ms
6,940 KB
testcase_06 AC 57 ms
6,940 KB
testcase_07 AC 389 ms
6,940 KB
testcase_08 AC 270 ms
6,940 KB
testcase_09 AC 349 ms
6,940 KB
testcase_10 AC 375 ms
6,944 KB
testcase_11 AC 324 ms
6,940 KB
testcase_12 AC 405 ms
6,940 KB
testcase_13 AC 478 ms
6,940 KB
testcase_14 AC 493 ms
6,940 KB
testcase_15 AC 487 ms
6,940 KB
testcase_16 AC 486 ms
6,940 KB
testcase_17 AC 482 ms
6,944 KB
testcase_18 AC 477 ms
6,940 KB
testcase_19 AC 481 ms
6,940 KB
testcase_20 AC 481 ms
6,944 KB
testcase_21 AC 479 ms
6,944 KB
testcase_22 AC 480 ms
6,940 KB
testcase_23 AC 427 ms
6,940 KB
testcase_24 AC 467 ms
6,940 KB
testcase_25 AC 445 ms
6,940 KB
testcase_26 AC 424 ms
6,944 KB
testcase_27 AC 328 ms
6,944 KB
testcase_28 AC 2 ms
6,940 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 # 

typedef long long ll;
typedef long double ld;
#include <bits/stdc++.h>
using namespace std;
#define int long long
// こっちを使おう！
// __builtin_popcountll
// 1<<n -> オーバーフロー




struct UnionFind {
    vector<int> par;

    UnionFind() { }
    UnionFind(int n) : par(n, -1) { }
    void init(int n) { par.assign(n, -1); }
    
    int root(int x) {
        if (par[x] < 0) return x;
        else return par[x] = root(par[x]);
    }
    
    bool issame(int x, int y) {
        return root(x) == root(y);
    }
    
    bool merge(int x, int y) {
        x = root(x); y = root(y);
        if (x == y) return false;
        if (par[x] > par[y]) swap(x, y); // merge technique
        par[x] += par[y];
        par[y] = x;
        return true;
    }
    
    int size(int x) {
        return -par[root(x)];
    }
};


// Segment Tree
template<class Monoid> struct SegTree {
    using Func = function<Monoid(Monoid, Monoid)>;
    int N;
    Func F;
    Monoid IDENTITY;
    int SIZE_R;
    vector<Monoid> dat;

    /* initialization */
    SegTree() {}
    SegTree(int n, const Func f, const Monoid &identity)
    : N(n), F(f), IDENTITY(identity) {
        SIZE_R = 1;
        while (SIZE_R < n) SIZE_R *= 2;
        dat.assign(SIZE_R * 2, IDENTITY);
    }
    void init(int n, const Func f, const Monoid &identity) {  
        N = n;
        F = f;
        IDENTITY = identity;
        SIZE_R = 1;
        while (SIZE_R < n) SIZE_R *= 2;
        dat.assign(SIZE_R * 2, IDENTITY);
    }
    
    /* set, a is 0-indexed */
    /* build(): O(N) */
    void set(int a, const Monoid &v) { dat[a + SIZE_R] = v; }
    void build() {
        for (int k = SIZE_R - 1; k > 0; --k)
            dat[k] = F(dat[k*2], dat[k*2+1]);
    }
    
    /* update a, a is 0-indexed, O(log N) */
    void update(int a, const Monoid &v) {
        int k = a + SIZE_R;
        dat[k] = v;
        while (k >>= 1) dat[k] = F(dat[k*2], dat[k*2+1]);
    }
    
    /* get [a, b), a and b are 0-indexed, O(log N) */
    Monoid get(int a, int b) {
        Monoid vleft = IDENTITY, vright = IDENTITY;
        for (int left = a + SIZE_R, right = b + SIZE_R; left < right; 
        left >>= 1, right >>= 1) {
            if (left & 1) vleft = F(vleft, dat[left++]);
            if (right & 1) vright = F(dat[--right], vright);
        }
        return F(vleft, vright);
    }
    Monoid all_get() { return dat[1]; }
    Monoid operator [] (int a) { return dat[a + SIZE_R]; }
    
    /* get max r that f(get(l, r)) = True (0-indexed), O(log N) */
    /* f(IDENTITY) need to be True */
    int max_right(const function<bool(Monoid)> f, int l = 0) {
        if (l == N) return N;
        l += SIZE_R;
        Monoid sum = IDENTITY;
        do {
            while (l % 2 == 0) l >>= 1;
            if (!f(F(sum, dat[l]))) {
                while (l < SIZE_R) {
                    l = l * 2;
                    if (f(F(sum, dat[l]))) {
                        sum = F(sum, dat[l]);
                        ++l;
                    }
                }
                return l - SIZE_R;
            }
            sum = F(sum, dat[l]);
            ++l;
        } while ((l & -l) != l);  // stop if l = 2^e
        return N;
    }

    /* get min l that f(get(l, r)) = True (0-indexed), O(log N) */
    /* f(IDENTITY) need to be True */
    int min_left(const function<bool(Monoid)> f, int r = -1) {
        if (r == 0) return 0;
        if (r == -1) r = N;
        r += SIZE_R;
        Monoid sum = IDENTITY;
        do {
            --r;
            while (r > 1 && (r % 2)) r >>= 1;
            if (!f(F(dat[r], sum))) {
                while (r < SIZE_R) {
                    r = r * 2 + 1;
                    if (f(F(dat[r], sum))) {
                        sum = F(dat[r], sum);
                        --r;
                    }
                }
                return r + 1 - SIZE_R;
            }
            sum = F(dat[r], sum);
        } while ((r & -r) != r);
        return 0;
    }
    
    /* debug */
    void print() {
        for (int i = 0; i < N; ++i) {
            cout << (*this)[i];
            if (i != N-1) cout << ",";
        }
        cout << endl;
    }
};
// modint
template<int MOD> struct Fp {
    long long val;
    constexpr Fp(long long v = 0) noexcept : val(v % MOD) {
        if (val < 0) val += MOD;
    }
    constexpr int getmod() const { return MOD; }
    constexpr Fp operator - () const noexcept {
        return val ? MOD - val : 0;
    }
    constexpr Fp operator + (const Fp& r) const noexcept { return Fp(*this) += r; }
    constexpr Fp operator - (const Fp& r) const noexcept { return Fp(*this) -= r; }
    constexpr Fp operator * (const Fp& r) const noexcept { return Fp(*this) *= r; }
    constexpr Fp operator / (const Fp& r) const noexcept { return Fp(*this) /= r; }
    constexpr Fp& operator += (const Fp& r) noexcept {
        val += r.val;
        if (val >= MOD) val -= MOD;
        return *this;
    }
    constexpr Fp& operator -= (const Fp& r) noexcept {
        val -= r.val;
        if (val < 0) val += MOD;
        return *this;
    }
    constexpr Fp& operator *= (const Fp& r) noexcept {
        val = val * r.val % MOD;
        return *this;
    }
    constexpr Fp& operator /= (const Fp& r) noexcept {
        long long a = r.val, b = MOD, u = 1, v = 0;
        while (b) {
            long long t = a / b;
            a -= t * b, swap(a, b);
            u -= t * v, swap(u, v);
        }
        val = val * u % MOD;
        if (val < 0) val += MOD;
        return *this;
    }
    constexpr bool operator == (const Fp& r) const noexcept {
        return this->val == r.val;
    }
    constexpr bool operator != (const Fp& r) const noexcept {
        return this->val != r.val;
    }
    friend constexpr istream& operator >> (istream& is, Fp<MOD>& x) noexcept {
        is >> x.val;
        x.val %= MOD;
        if (x.val < 0) x.val += MOD;
        return is;
    }
    friend constexpr ostream& operator << (ostream& os, const Fp<MOD>& x) noexcept {
        return os << x.val;
    }
    friend constexpr Fp<MOD> modpow(const Fp<MOD>& r, long long n) noexcept {
        if (n == 0) return 1;
        if (n < 0) return modpow(modinv(r), -n);
        auto t = modpow(r, n / 2);
        t = t * t;
        if (n & 1) t = t * r;
        return t;
    }
    friend constexpr Fp<MOD> modinv(const Fp<MOD>& r) noexcept {
        long long a = r.val, b = MOD, u = 1, v = 0;
        while (b) {
            long long t = a / b;
            a -= t * b, swap(a, b);
            u -= t * v, swap(u, v);
        }
        return Fp<MOD>(u);
    }
};


// const int MOD = 1000000007;
// const int MOD = 998244353;
// using mint = Fp<MOD>;


// // Binomial coefficient
// template<class T> struct BiCoef {
//     vector<T> fact_, inv_, finv_;
//     constexpr BiCoef() {}
//     constexpr BiCoef(int n) noexcept : fact_(n, 1), inv_(n, 1), finv_(n, 1) {
//         init(n);
//     }
//     constexpr void init(int n) noexcept {
//         fact_.assign(n, 1), inv_.assign(n, 1), finv_.assign(n, 1);
//         int MOD = fact_[0].getmod();
//         for(int i = 2; i < n; i++){
//             fact_[i] = fact_[i-1] * i;
//             inv_[i] = -inv_[MOD%i] * (MOD/i);
//             finv_[i] = finv_[i-1] * inv_[i];
//         }
//     }
//     constexpr T com(int n, int k) const noexcept {
//         if (n < k || n < 0 || k < 0) return 0;
//         return fact_[n] * finv_[k] * finv_[n-k];
//     }
//     constexpr T fact(int n) const noexcept {
//         if (n < 0) return 0;
//         return fact_[n];
//     }
//     constexpr T inv(int n) const noexcept {
//         if (n < 0) return 0;
//         return inv_[n];
//     }
//     constexpr T finv(int n) const noexcept {
//         if (n < 0) return 0;
//         return finv_[n];
//     }
// };

// BiCoef<mint> bc;

signed main(){
    ll n,q;
    std::cin >> n>>q;
    UnionFind uf(n);
    
    for (int i = 0; i < n; i++) {
        ll p;
        std::cin >> p;
        if(p==-1)continue;
        p--;
        uf.merge(i,p);
    }
    for (int i = 0; i < q; i++) {
        ll a,b;
        std::cin >> a>>b;
        a--;b--;
        if(uf.issame(a,b)){
            std::cout << "Yes" << std::endl;
        }else{
            std::cout << "No" << std::endl;
        }
    }
}
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