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NOI.AC

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#213967#2380. 中位数nodgd1001141ms5884kbC++111.1kb2024-11-14 20:16:082024-11-14 23:05:44

answer

#include <bits/stdc++.h>

using namespace std;

const int MAX_N = 300000 + 5;

int N, A, a[MAX_N], av[MAX_N];
int c[MAX_N << 1];

bool check(int m) {
    for (int i = 1; i <= N << 1; i ++) {
        c[i] = 0;
    }
    long long cnt = 0;
    for (int i = 1, s = N; i <= N; i ++) {
        for (int j = s; j >= 1; j -= j & -j) {
            c[j] ++;
        }
        s += a[i] <= m ? -1 : 1;
        for (int j = s; j <= N << 1; j += j & -j) {
            cnt += c[j];
        }
    }
    return cnt >= N * (N + 1ll) / 2 + 1 >> 1;
}

int main() {
    scanf("%d", &N);
    for (int i = 1; i <= N; i ++) {
        scanf("%d", &a[i]);
        av[i] = a[i];
    }
    sort(av + 1, av + 1 + N);
    A = unique(av + 1, av + 1 + N) - av - 1;
    for (int i = 1; i <= N; i ++) {
        a[i] = lower_bound(av + 1, av + 1 + A, a[i]) - av;
    }
    int l = 1, r = A;
    while (l < r) {
        int mid = l + r >> 1;
        if (check(mid)) {
            r = mid;
        } else {
            l = mid + 1;
        }
    }
    printf("%d\n", av[l]);
    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: 1216kb

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: 1216kb

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: 1220kb

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: 3ms
memory: 1288kb

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: 3ms
memory: 1284kb

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: 3ms
memory: 1284kb

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: 250ms
memory: 5880kb

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: 362ms
memory: 5884kb

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: 259ms
memory: 5880kb

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: 261ms
memory: 5884kb

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