Submission #486221

#	Time	Username	Problem	Language	Result	Execution time	Memory
486221		diedie	Index (COCI21_index)	C++17	110 / 110	335 ms	51056 KiB

index

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

using ll = long long;
using pi32 = pair<int, int>;
using pi64 = pair<int64_t, int64_t>;

const int maxN = 2e5 + 5;
const int maxC = 10000000;
const ll INF = 2e18 + 7;
const int MOD = 998244353;

int n, nTest;
int idx;

struct Segment {
    int left, right, val;
} st[maxC];

void init (int id, int l, int r){
    if (l == r) return;

    int mid = (l + r) / 2;
    st[id].left = ++idx;
    st[id].right = ++idx;
    init(st[id].left, l, mid);
    init(st[id].right, mid + 1, r);
}

void update (int id, int pos, int l, int r, int h) {
    if (l == r) {
        st[id].val = st[pos].val + 1;
        return;
    }

    int mid = (l + r) / 2;
    st[id].left = st[pos].left;
    st[id].right = st[pos].right;
    if (h <= mid) {
        st[id].left = ++idx;
        update(st[id].left, st[pos].left, l, mid, h);
    }
    else {
        st[id].right = ++idx;
        update(st[id].right, st[pos].right, mid + 1, r, h);
    }
    st[id].val = st[st[id].left].val + st[st[id].right].val;
}

int root[maxN];

int query (int id, int pos, int l, int r, int add) {
    if (l == r) return l;

    int mid = (l + r) / 2;
    int tmp = st[st[id].right].val - st[st[pos].right].val + add;
    if (tmp >= mid + 1)
        return query(st[id].right, st[pos].right, mid + 1, r, add);
    else return query(st[id].left, st[pos].left, l, mid, tmp);
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> n >> nTest;
    idx = 1;
    root[0] = 1;
    init(1, 1, n);
    for (int i = 1; i <= n; ++i) {
        int h; cin >> h;
        root[i] = root[i - 1];
        int old = root[i];
        root[i] = ++idx;
        update(root[i], old, 1, n, h);
    }

    while (nTest--) {
        int l, r; cin >> l >> r;
        cout << query(root[r], root[l-1], 1, n, 0) << '\n';
    }

    return 0;
}

• Subtask 1: 20 / 20
• Subtask 2: 40 / 40
• Subtask 3: 50 / 50