Submission #755447

#	Time	Username	Problem	Language	Result	Execution time	Memory
755447		MilosMilutinovic	Izbori (COCI22_izbori)	C++14	40 / 110	3058 ms	2264 KiB

Main

#include <bits/stdc++.h>
using namespace std;
const int N = 2e5 + 10;
const int M = 2 * N;
const int B = 2 * sqrt(N);
int n, a[N], c[M], cnt[N], occ[N];
void modify(int p, int v) {
    for (p += N; p < M; p += p & -p) c[p] += v;
}
int query(int p) {
    int res = 0;
    for (p += N; p > 0; p -= p & -p) res += c[p];
    return res;
}
void compress() {
    vector<int> xs;
    for (int i = 1; i <= n; i++)
        xs.push_back(a[i]);
    sort(xs.begin(), xs.end());
    xs.erase(unique(xs.begin(), xs.end()), xs.end());
    for (int i = 1; i <= n; i++) {
        a[i] = (int) (lower_bound(xs.begin(), xs.end(), a[i]) - xs.begin()) + 1;
    }
}
int main() {
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) {
        scanf("%d", &a[i]);
    }
    compress();
    for (int i = 1; i <= n; i++) {
        occ[a[i]] += 1;
    }
    long long ans = 0;
    for (int v = 1; v <= n; v++) {
        if (occ[v] >= B) {
            modify(0, +1);
            int bal = 0;
            for (int i = 1; i <= n; i++) {
                bal += (a[i] == v ? 1 : -1);
                ans += query(bal - 1);
                modify(bal, +1);
            }
            modify(0, -1);
            bal = 0;
            for (int i = 1; i <= n; i++) {
                bal += (a[i] == v ? 1 : -1);
                modify(bal, -1);
            }
        }
    }
    for (int l = 1; l <= n; l++) {
        int f = a[l];
        for (int r = l; r <= min(l + 2 * B, n); r++) {
            cnt[a[r]] += 1;
            if (cnt[a[r]] > cnt[f])
                f = a[r];
            if (cnt[f] * 2 > r - l + 1 && occ[f] < B)
                ans++;
        }
        for (int r = l; r <= min(l + 2 * B, n); r++) {
            cnt[a[r]] = 0;
        }
    }
    printf("%lld", ans);
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:26:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   26 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
Main.cpp:28:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   28 |         scanf("%d", &a[i]);
      |         ~~~~~^~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 15 / 15
• Subtask 4: 0 / 70