Submission #577119

#	Time	Username	Problem	Language	Result	Execution time	Memory
577119		eecs	Exercise Deadlines (CCO20_day1problem2)	C++17	25 / 25	91 ms	6192 KiB

Main

#include <bits/stdc++.h>
using namespace std;

const int maxn = 200010;
int n, d[maxn], p[maxn];

#define mid ((l + r) >> 1)
#define ls (k << 1)
#define rs (k << 1 | 1)
int mx[maxn << 2];

void build(int k, int l, int r) {
    if (l == r) { mx[k] = d[l]; return; }
    build(ls, l, mid), build(rs, mid + 1, r);
    mx[k] = max(mx[ls], mx[rs]);
}

void upd(int k, int l, int r, int p) {
    if (l == r) { mx[k] = 0; return; }
    mid >= p ? upd(ls, l, mid, p) : upd(rs, mid + 1, r, p);
    mx[k] = max(mx[ls], mx[rs]);
}

int find(int k, int l, int r, int v) {
    if (l == r) return l;
    return mx[rs] >= v ? find(rs, mid + 1, r, v) : find(ls, l, mid, v);
}

namespace BIT {
int c[maxn];

void add(int p, int v) {
    for (; p <= n; p += p & -p) c[p] += v;
}

int sum(int p) {
    int s = 0;
    for (; p; p -= p & -p) s += c[p];
    return s;
}
} // namespace BIT

int main() {
    ios::sync_with_stdio(0), cin.tie(0);
    cin >> n;
    for (int i = 1; i <= n; i++) {
        cin >> d[i];
    }
    build(1, 1, n);
    for (int i = n; i; i--) {
        if (mx[1] < i) puts("-1"), exit(0);
        int j = find(1, 1, n, i);
        p[j] = i, upd(1, 1, n, j);
    }
    long long ans = 0;
    for (int i = n; i; i--) {
        ans += BIT::sum(p[i]), BIT::add(p[i], 1);
    }
    cout << ans << "\n";
    return 0;
}

• Subtask 1: 17 / 17
• Subtask 2: 8 / 8