Submission #862803

#	Time	Username	Problem	Language	Result	Execution time	Memory
862803		deepaung	Index (COCI21_index)	C++14	110 / 110	476 ms	202408 KiB

index

#include <bits/stdc++.h>

#define f first
#define s second
#define ll long long
#define pii pair<int, int>

using namespace std;

struct node {
    int val, left_idx, right_idx;
    node *l, *r;

    node(int val, int left_idx=0, int right_idx=0, node *l=NULL, node *r=NULL) : 
        val(val), left_idx(left_idx), right_idx(right_idx), l(l), r(r) {}

};

int n, w;
int p[200002];
node *seg[200002];

node* build(int l, int r) {
    if (l == r) return new node(0, l, l);

    int mid = (l + r) >> 1;
    node *resl = build(l, mid);
    node *resr = build(mid+1, r);

    return new node(
        resl->val + resr->val, 
        resl->left_idx, 
        resr->right_idx, 
        resl, 
        resr
    );
}

void upgrade(node *pre, node *cur, int i, int val, int l, int r) {
    if (l == r) {
        cur->val = pre->val + val;
        cur->left_idx = l;
        cur->right_idx = l;
        return;
    }

    int mid = (l + r) >> 1;
    if (i <= mid) {
        cur->l = new node(0);
        cur->r = pre->r;
        upgrade(pre->l, cur->l, i, val, l, mid);
    } else {
        cur->l = pre->l;
        cur->r = new node(0);
        upgrade(pre->r, cur->r, i, val, mid+1, r);
    }

    cur->val = cur->l->val + cur->r->val;
    cur->left_idx = cur->l->left_idx;
    cur->right_idx = cur->r->right_idx;
}

int findd(node *right, node *left, int add, int l, int r) {
    if (l == r) {
        return l;
    }

    int mid = (l + r) >> 1;

    int val = right->r->val - left->r->val + add;
    int left_idx = right->r->left_idx;

    if (left_idx <= val) {
        return findd(right->r, left->r, add, mid+1, r);
    } else {
        return findd(right->l, left->l, val, l, mid);
    }
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);

    cin >> n >> w;
    for (int i = 1; i <= n; i++) cin >> p[i];

    seg[0] = build(1, 200000);
    // cout << seg[0]->r->left_idx << " " << seg[0]->l->right_idx << "\n";
    for (int i = 1; i <= n; i++) {
        seg[i] = new node(0);
        upgrade(seg[i-1], seg[i], p[i], 1, 1, 200000);
    }

    // cout << "hello\n";

    // return 0;

    int l, r;
    while (w--) {
        cin >> l >> r;
        int ans = findd(seg[r], seg[l-1], 0, 1, 200000);
        // for (auto it : res) cout << it << " "; cout << "\n";
        cout << ans << "\n";
    }

    return 0;
}

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