ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
---|---|---|---|---|---|---|---|---|---|
#213924 | #2380. 中位数 | N | 100 | 1069ms | 5960kb | C++11 | 1.9kb | 2024-11-14 19:09:24 | 2024-11-14 23:01:50 |
answer
//
// na 2380.cpp
// Competitive Programming
//
// Created by m2 on 2024/11/14.
//
#include <stdio.h>
#include <iostream>
#include <algorithm>
#include <string.h>
#include <vector>
using namespace std;
typedef long long int ll;
const int maxn = 3e5 + 5;
int n, a[maxn], vs[maxn], vl;
struct Tree{
#define lowbit(x) (x & -x)
static const int lim = maxn * 2;
int val[lim];
inline void insert(int pos, int dv){
for(; pos < lim; pos += lowbit(pos))
val[pos] += dv;
}
inline int query(int lim){
int res = 0;
for(; lim; lim -= lowbit(lim))
res += val[lim];
return res;
}
#undef lowbit
inline void clear(){
memset(val, 0, sizeof(val));
}
}tree;
inline ll check(int lim){
// cerr << "check " << lim << endl;
ll res = 0;
tree.clear();
int base = n + 1;
tree.insert(base, 1);
for(int i = 0; i < n; ++i){
base += a[i] >= lim? 1: -1;
res += tree.query(base - 1);
tree.insert(base, 1);
}
// cerr << "res: " << res << " intervals" << endl;
return res;
}
#define READFILE
int main(){
#if defined(MAC_OS_VERSION_11_0) && defined(READFILE)
freopen("/Users/m2/Downloads/problem_2380/ex_median2.in", "r", stdin);
#endif
cin.tie(0)->sync_with_stdio(false);
cin >> n;
for(int i = 0; i < n; ++i){
cin >> a[i];
vs[i] = a[i];
}
sort(vs, vs + n);
vl = int(unique(vs, vs + n) - vs);
for(int i = 0; i < n; ++i)
a[i] = int(lower_bound(vs, vs + vl, a[i]) - vs);
// cerr << "a = { ";
// for(int i = 0; i < n; ++i)
// cerr << a[i] << ' ';
// cerr << "}" << endl;
int lt = 0, rt = vl, mid;
ll rank = ((ll(n + 1) * n / 2) + 1) / 2;
while(lt < rt - 1){
mid = (lt + rt) >> 1;
if(check(mid) >= rank)
lt = mid;
else
rt = mid;
}
cout << vs[lt] << endl;
return 0;
}
Details
小提示:点击横条可展开更详细的信息
Test #1:
score: 10
Accepted
time: 0ms
memory: 3616kb
input:
200 247837946 222748444 549404903 934970141 181690491 116150147 755881953 912914845 578004877 589768...
output:
411892743
result:
ok 1 number(s): "411892743"
Test #2:
score: 10
Accepted
time: 0ms
memory: 3616kb
input:
200 504553675 321343511 781936447 172776833 779139954 643752948 106 164 303976944 828799931 11502170...
output:
451369372
result:
ok 1 number(s): "451369372"
Test #3:
score: 10
Accepted
time: 0ms
memory: 3616kb
input:
200 738368650 91602659 340556191 835209882 409442204 656938221 258295858 90658347 126689369 56196859...
output:
420852999
result:
ok 1 number(s): "420852999"
Test #4:
score: 10
Accepted
time: 6ms
memory: 3656kb
input:
5000 300051244 685920750 122806687 315801142 33592358 339985437 262520930 380010194 687330910 550362...
output:
465193387
result:
ok 1 number(s): "465193387"
Test #5:
score: 10
Accepted
time: 6ms
memory: 3660kb
input:
5000 108135249 950186870 146626753 682580494 744412491 4159 995071655 157947560 668940645 878891308 ...
output:
466892796
result:
ok 1 number(s): "466892796"
Test #6:
score: 10
Accepted
time: 6ms
memory: 3660kb
input:
5000 246610103 780664789 678774940 716124165 518453378 300121008 135383319 939869983 430946660 13412...
output:
470507384
result:
ok 1 number(s): "470507384"
Test #7:
score: 10
Accepted
time: 259ms
memory: 5960kb
input:
300000 786856547 380253059 684225515 795392038 881780483 18437791 793783577 832330260 801624996 3466...
output:
463539280
result:
ok 1 number(s): "463539280"
Test #8:
score: 10
Accepted
time: 263ms
memory: 5956kb
input:
300000 951000485 930070933 3566360 157114366 150196488 611226665 123590886 950624066 472150346 57976...
output:
462334620
result:
ok 1 number(s): "462334620"
Test #9:
score: 10
Accepted
time: 270ms
memory: 5956kb
input:
300000 728509094 406128756 696166390 756254976 31403187 672131182 35544213 870708756 3659210 5227553...
output:
464162969
result:
ok 1 number(s): "464162969"
Test #10:
score: 10
Accepted
time: 259ms
memory: 5956kb
input:
300000 804874490 52247250 546638789 400214210 383796618 47995083 814777769 507157584 466189162 28296...
output:
463577194
result:
ok 1 number(s): "463577194"
Extra Test:
score: 0
Extra Test Passed