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ID题目提交者结果用时内存语言文件大小提交时间测评时间
#213964#2380. 中位数KXG60982ms7536kbC++111.5kb2024-11-14 20:11:002024-11-14 23:05:36

answer

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
struct BIT {
    int n = 600000, t[600010];
    void modify(int k, int x) {
        k += 300000;
        for (int i = k; i <= n; i += i & (-i)) {
            t[i] += x;
        }
    }
    int query(int k) {
        k += 300000;
        int ans = 0;
        for (int i = k; i >= 1; i -= i & (-i)) {
            ans += t[i];
        }
        return ans;
    }
    int query(int l, int r) {
        return query(r) - query(l - 1);
    }
} bt;
int n, a[300010], b[300010];
pair<int, int> s[300010];
int solve(pair<int, int> x) {
    for (int i = 1; i <= n; i++) {
        if (make_pair(a[i], i) <= x) {
            b[i] = -1;
        } else if (make_pair(a[i], i) > x) {
            b[i] = 1;
        }
    }
    memset(bt.t, 0, sizeof(bt.t));
    bt.modify(0, 1);
    int res = 0;
    for (int i = 1; i <= n; i++) {
        b[i] += b[i - 1];
        res += i - bt.query(b[i] - 1);
        bt.modify(b[i], 1);
    }
    return res;
}
int main() {
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) {
        scanf("%d", &a[i]);
        s[i] = make_pair(a[i], i);
    }
    sort(s + 1, s + n + 1);
    int tot = (n * (n + 1) / 2 + 1) / 2;
    int l = 1, r = n, ans = 0;
    while (l <= r) {
        int mid = (l + r) >> 1;
        int ck = solve(s[mid]);
        if (ck >= tot) {
            ans = mid;
            r = mid - 1;
        } else {
            l = mid + 1;
        }
    }
    printf("%d\n", s[ans]);
    return 0;
}

详细

小提示:点击横条可展开更详细的信息

Test #1:

score: 10
Accepted
time: 4ms
memory: 5208kb

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: 5204kb

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: 2ms
memory: 5204kb

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: 14ms
memory: 5240kb

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: 4ms
memory: 5236kb

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: 5236kb

input:

5000
246610103 780664789 678774940 716124165 518453378 300121008 135383319 939869983 430946660 13412...

output:

470507384

result:

ok 1 number(s): "470507384"

Test #7:

score: 0
Wrong Answer
time: 241ms
memory: 7532kb

input:

300000
786856547 380253059 684225515 795392038 881780483 18437791 793783577 832330260 801624996 3466...

output:

733296693

result:

wrong answer 1st numbers differ - expected: '463539280', found: '733296693'

Test #8:

score: 0
Wrong Answer
time: 239ms
memory: 7532kb

input:

300000
951000485 930070933 3566360 157114366 150196488 611226665 123590886 950624066 472150346 57976...

output:

506060058

result:

wrong answer 1st numbers differ - expected: '462334620', found: '506060058'

Test #9:

score: 0
Wrong Answer
time: 244ms
memory: 7536kb

input:

300000
728509094 406128756 696166390 756254976 31403187 672131182 35544213 870708756 3659210 5227553...

output:

509103066

result:

wrong answer 1st numbers differ - expected: '464162969', found: '509103066'

Test #10:

score: 0
Wrong Answer
time: 228ms
memory: 7536kb

input:

300000
804874490 52247250 546638789 400214210 383796618 47995083 814777769 507157584 466189162 28296...

output:

2629

result:

wrong answer 1st numbers differ - expected: '463577194', found: '2629'