제출 #1313420

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1313420		chithanhnguyen	Advertisement 2 (JOI23_ho_t2)	C++20	100 / 100	335 ms	12272 KiB

Main

/*
Author: Nguyen Chi Thanh - High School for the Gifted - VNU.HCM (i2528)
*/
#include <bits/stdc++.h>
using namespace std;

// #define int long long
#define ull unsigned long long
#define ld long double
#define pii pair<int, int>
#define fi first
#define se second
#define __builtin_popcount __builtin_popcountll
#define all(x) (x).begin(), (x).end()
#define BIT(x, i) (((x) >> (i)) & 1)
#define MASK(x) ((1ll << (x)))

#define debug(a, l, r) for (int _i = (l); _i <= (r); ++_i) cout << (a)[_i] << ' '; cout << '\n';

// Data structures
struct Normalize {
    vector<int> vals;

    Normalize() {}
    void add(int v) {vals.push_back(v);}
    void build() {
        sort(all(vals));
        vals.erase(unique(all(vals)), end(vals));
    }

    int compress(int v) {
        return (int)(lower_bound(all(vals), v) - begin(vals)) + 1;
    }
};

struct FenwickTree{
    int n;
    vector<int> fen;

    FenwickTree(int _n) : n(_n), fen(n + 5, 0) {}

    void update(int idx, int v) {
        for (int i = idx; i <= n; i += i & -i)
            fen[i] += v;
    }

    int get(int idx) {
        int sum = 0;
        for (int i = idx; i; i -= i & -i)
            sum += fen[i];
        return sum;
    }

    int query(int l, int r) {return get(r) - get(l - 1);}
};

// Main program
const int MAXN = 5e5 + 5;
int n, x[MAXN], e[MAXN];
pii segs[MAXN];

void init() {
    cin >> n;

    Normalize norm; 
    for (int i = 1; i <= n; ++i) {
        cin >> x[i] >> e[i];
        segs[i] = {x[i] - e[i], x[i] + e[i]};
        norm.add(segs[i].fi);
        norm.add(segs[i].se);
    }

    // Coords compression
    norm.build();
    for (int i = 1; i <= n; ++i) {
        segs[i].fi = norm.compress(segs[i].fi);
        segs[i].se = norm.compress(segs[i].se);
    }

    // for (int i = 1; i <= n; ++i) cout << segs[i].fi << ' ' << segs[i].se << '\n';
}

void solve() {
    sort(segs + 1, segs + n + 1, [&] (pii &i, pii &j) {
        if (i.fi == j.fi) return i.se > j.se;
        return i.fi < j.fi;
    });

    FenwickTree fen(2 * n + 5);
    int res = 0;
    for (int i = 1; i <= n; ++i) {
        int l = segs[i].fi, r = segs[i].se;
        if (fen.query(r, 2 * n + 5) == 0)
            ++res;

        fen.update(r, 1);
    }

    cout << res;
}

signed main() {
    #ifdef NCTHANH
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    #endif
    ios_base::sync_with_stdio(0);
    cin.tie(nullptr); cout.tie(nullptr);

    init();
    solve();

    return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 23 / 23
• Subtask 3: 36 / 36
• Subtask 4: 31 / 31