#1187026 (C++23) No.1526 Sum of Mex 2

• 問題: No.1526 Sum of Mex 2
• ユーザー: karinohito
• 提出日時: 2026-09-16 13:58:48
• 言語: C++23 (gcc 15.3.0 + boost 1.92.0 + ACL)
• 結果: AC
• 実行時間: 186 ms / 3,000 ms
• コード長: 6,574 bytes
• コンパイル時間: 2,646 ms
• コンパイル使用メモリ: 357,352 KB
• 実行使用メモリ: 25,284 KB
• 最終ジャッジ日時: 2026-09-16 13:58:57
• 合計ジャッジ時間: 9,211 ms
• ジャッジサーバーID （参考情報）: judge3_0 / judge2_0

ファイルパターン	結果
sample	AC * 3
other	AC * 32

ソースコード

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


// acl を beats! するやつ 参考: https://rsm9.hatenablog.com/entry/2021/02/01/220408
int ceil_pow2(int n) {
    int x = 0;
    while ((1U << x) < (unsigned int)(n)) x++;
    return x;
}

namespace atcoder {

template <class S,
          S (*op)(S, S),
          S (*e)(),
          class F,
          S (*mapping)(F, S),
          F (*composition)(F, F),
          F (*id)()>
struct lazy_segtree {
  public:
    lazy_segtree() : lazy_segtree(0) {}
    lazy_segtree(int n) : lazy_segtree(std::vector<S>(n, e())) {}
    lazy_segtree(const std::vector<S>& v) : _n(int(v.size())) {
        log = ceil_pow2(_n);
        size = 1 << log;
        d = std::vector<S>(2 * size, e());
        lz = std::vector<F>(size, id());
        for (int i = 0; i < _n; i++) d[size + i] = v[i];
        for (int i = size - 1; i >= 1; i--) {
            update(i);
        }
    }

    void set(int p, S x) {
        assert(0 <= p && p < _n);
        p += size;
        for (int i = log; i >= 1; i--) push(p >> i);
        d[p] = x;
        for (int i = 1; i <= log; i++) update(p >> i);
    }

    S get(int p) {
        assert(0 <= p && p < _n);
        p += size;
        for (int i = log; i >= 1; i--) push(p >> i);
        return d[p];
    }

    S prod(int l, int r) {
        assert(0 <= l && l <= r && r <= _n);
        if (l == r) return e();

        l += size;
        r += size;

        for (int i = log; i >= 1; i--) {
            if (((l >> i) << i) != l) push(l >> i);
            if (((r >> i) << i) != r) push(r >> i);
        }

        S sml = e(), smr = e();
        while (l < r) {
            if (l & 1) sml = op(sml, d[l++]);
            if (r & 1) smr = op(d[--r], smr);
            l >>= 1;
            r >>= 1;
        }

        return op(sml, smr);
    }

    S all_prod() { return d[1]; }

    void apply(int p, F f) {
        assert(0 <= p && p < _n);
        p += size;
        for (int i = log; i >= 1; i--) push(p >> i);
        d[p] = mapping(f, d[p]);
        for (int i = 1; i <= log; i++) update(p >> i);
    }
    void apply(int l, int r, F f) {
        assert(0 <= l && l <= r && r <= _n);
        if (l == r) return;

        l += size;
        r += size;

        for (int i = log; i >= 1; i--) {
            if (((l >> i) << i) != l) push(l >> i);
            if (((r >> i) << i) != r) push((r - 1) >> i);
        }

        {
            int l2 = l, r2 = r;
            while (l < r) {
                if (l & 1) all_apply(l++, f);
                if (r & 1) all_apply(--r, f);
                l >>= 1;
                r >>= 1;
            }
            l = l2;
            r = r2;
        }

        for (int i = 1; i <= log; i++) {
            if (((l >> i) << i) != l) update(l >> i);
            if (((r >> i) << i) != r) update((r - 1) >> i);
        }
    }

    template <bool (*g)(S)> int max_right(int l) {
        return max_right(l, [](S x) { return g(x); });
    }
    template <class G> int max_right(int l, G g) {
        assert(0 <= l && l <= _n);
        assert(g(e()));
        if (l == _n) return _n;
        l += size;
        for (int i = log; i >= 1; i--) push(l >> i);
        S sm = e();
        do {
            while (l % 2 == 0) l >>= 1;
            if (!g(op(sm, d[l]))) {
                while (l < size) {
                    push(l);
                    l = (2 * l);
                    if (g(op(sm, d[l]))) {
                        sm = op(sm, d[l]);
                        l++;
                    }
                }
                return l - size;
            }
            sm = op(sm, d[l]);
            l++;
        } while ((l & -l) != l);
        return _n;
    }

    template <bool (*g)(S)> int min_left(int r) {
        return min_left(r, [](S x) { return g(x); });
    }
    template <class G> int min_left(int r, G g) {
        assert(0 <= r && r <= _n);
        assert(g(e()));
        if (r == 0) return 0;
        r += size;
        for (int i = log; i >= 1; i--) push((r - 1) >> i);
        S sm = e();
        do {
            r--;
            while (r > 1 && (r % 2)) r >>= 1;
            if (!g(op(d[r], sm))) {
                while (r < size) {
                    push(r);
                    r = (2 * r + 1);
                    if (g(op(d[r], sm))) {
                        sm = op(d[r], sm);
                        r--;
                    }
                }
                return r + 1 - size;
            }
            sm = op(d[r], sm);
        } while ((r & -r) != r);
        return 0;
    }

  private:
    int _n, size, log;
    std::vector<S> d;
    std::vector<F> lz;

    void update(int k) { d[k] = op(d[2 * k], d[2 * k + 1]); }
    void all_apply(int k, F f) {
        d[k] = mapping(f, d[k]);
        if (k < size) {
            lz[k] = composition(f, lz[k]);
            if (d[k].fail) push(k), update(k);
        }
    }
    void push(int k) {
        all_apply(2 * k, lz[k]);
        all_apply(2 * k + 1, lz[k]);
        lz[k] = id();
    }
};

}  // namespace atcoder

ll second_min(ll a0,ll a1,ll b0,ll b1){
    if(a0==b0)return min(a1,b1);
    else if(a0<b0)return min(a1,b0);
    else return min(a0,b1);
}
struct S{
    ll m0,m1,nm,sm;//最小, secondmin, num of min, sum
    bool fail;
};
S mk(ll x){
    return S({x,ll(1e18),1,x,0});
}
S e(){
    return S({ll(1e18),ll(1e18),0,0,0});
};
S op(S L,S R){
    S res;
    res.m0=min(L.m0,R.m0);
    res.nm=L.nm*(L.m0<=R.m0)+R.nm*(L.m0>=R.m0);
    res.m1=second_min(L.m0,L.m1,R.m0,R.m1);
    res.sm=L.sm+R.sm;
    res.fail=0;
    return res;
}
ll comp(ll L,ll R){
    return max(L,R);
}

ll id(){return -1;}

S mapping(ll f,S x){
    if(f<=x.m0||x.nm==0||f==-1){
        x.fail=0;
        return x;
    }
    else if(f<x.m1){
        x.sm+=(f-x.m0)*x.nm;
        x.m0=f;
        x.fail=0;
        return x;
    }
    else{
        x.fail=1;
        return x;
    }
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    ll N;
    cin>>N;
    vector<ll> A(N);
    vector<vector<ll>> CA(N+1);
    for(int i=0;i<N;i++){
        cin>>A[i];
        A[i]--;
        CA[A[i]].push_back(i);
    }
    for(int i=0;i<=N;i++)CA[i].push_back(N);
    ll x=0;
    vector<S> R(N);
    for(int i=0;i<N;i++){
        R[i]=mk(i);
    }
    ll an=0;
    atcoder::lazy_segtree<S,op,e,ll,mapping,comp,id> seg(R);
    for(int k=0;k<=N;k++){
        x=0;
        for(int i=0;i<CA[k].size();i++){
            seg.apply(x,CA[k][i],CA[k][i]);
            x=CA[k][i]+1;
        }
        an+=N*N-seg.all_prod().sm;
    }
    cout<<an+N*(N+1)/2<<"\n";
    
}