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
(要ログイン)
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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