結果

問題 No.2077 Get Minimum Algorithm
ユーザー HYEA LEE
提出日時 2022-01-20 11:57:56
言語 C++17(clang)
(17.0.6 + boost 1.87.0)
結果
AC  
実行時間 1,333 ms / 3,000 ms
コード長 3,021 bytes
コンパイル時間 3,353 ms
コンパイル使用メモリ 163,656 KB
実行使用メモリ 26,496 KB
最終ジャッジ日時 2024-12-21 17:56:53
合計ジャッジ時間 25,232 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge3
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 36
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 #
プレゼンテーションモードにする

#include<bits/stdc++.h>
using namespace std;
namespace wtree
{
    const int MAXN = 100000 * 2;
    const int INF = 0x3f3f3f3f;
    int sz[MAXN];
    int* wavelet[MAXN];
    int* leftsum[MAXN];
    int lc[MAXN]; //left child
    int rc[MAXN]; //right child
    int sr[MAXN]; //start range
    int er[MAXN]; //end range
    int tp = 0;
    void build(int x)
    {
        int s = sr[x], e = er[x], m = (s+e)>>1, N = sz[x], ls = 0;
        lc[x] = rc[x] = -1;
        leftsum[x] = (int*) malloc(sizeof(int)*(N+1));
        leftsum[x][0] = 0;
        for(int i=1; i<=N; ++i)
        {
            if(wavelet[x][i] <= m) ++ls;
            leftsum[x][i] = ls;
        }
        if(s==e) return;
        lc[x] = tp; sr[tp] = er[tp] = s; sz[tp] = ls;
        wavelet[tp] = (int*) malloc(sizeof(int)*sz[tp]) - 1;
        tp++;
        rc[x] = tp; sr[tp] = er[tp] = e; sz[tp] = N-ls;
        wavelet[tp] = (int*) malloc(sizeof(int)*sz[tp]) - 1;
        tp++;
        int ind1 = 0, ind2 = 0;
        for(int i=1; i<=N; ++i)
        {
            if(wavelet[x][i] <= m)
            {
                wavelet[lc[x]][++ind1] = wavelet[x][i];
                er[lc[x]] = max(er[lc[x]], wavelet[x][i]);
            }
            else
            {
                wavelet[rc[x]][++ind2] = wavelet[x][i];
                sr[rc[x]] = min(sr[rc[x]], wavelet[x][i]);
            }
        }
        build(lc[x]); build(rc[x]);
        free(wavelet[x]+1);
        return;
    }
    int getKth(int s, int e, int k, int idx = 0)
    {
        // cout << s << " " << e << " " << k << " " << idx << endl;
        if(sr[idx]==er[idx]) return sr[idx];
        int lcount = leftsum[idx][e]-leftsum[idx][s-1];
        if(k<=lcount)
            return getKth(leftsum[idx][s-1]+1, leftsum[idx][e], k, lc[idx]);
        else
            return getKth(s-leftsum[idx][s-1], e-leftsum[idx][e], k-lcount, rc[idx]);
    }
}
using namespace wtree;
int main()
{
    ios::sync_with_stdio(false); cin.tie(0);
    int N; cin >> N; int* P = (int*) malloc(sizeof(int)*N)-1;
    sz[tp] = N; wavelet[tp] = (int*) malloc(sizeof(int)*N)-1;
    sr[tp] = INF; er[tp] = -INF;
    int *inv = (int*) malloc(sizeof(int)*N)-1;
    for(int i=1; i<=N; ++i)
    {
        cin >> P[i]; wavelet[tp][i] = P[i]; inv[P[i]] = i;
        sr[tp] = min(sr[tp], P[i]); er[tp] = max(er[tp], P[i]);
    }
    build(tp++);
    int Q; cin >> Q; while(Q--)
    {
        int x, y; cin >> x >> y;
        // P_{x,y} = max(P_y,(x+1th elem of P_1,P_2,...,P_y))
        // first check whether P_{x, inv(y)} = y
        if(inv[y] >= x+1 && getKth(1, inv[y], x+1) <= y) cout << inv[y] << '\n';
        else
        {
            // answer is not in [y, lo], but in [y, hi]
            int lo = max(x, inv[y]), hi = N;
            // cout << lo << " " << hi << endl;
            while(lo+1!=hi)
            {
                int mi = (lo+hi)/2;
                if(getKth(1, mi, x+1) <= y) hi = mi;
                else lo = mi;
            }
            cout << hi << '\n';
        }
    }
}
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