Submission #1078851

#	Time	Username	Problem	Language	Result	Execution time	Memory
1078851		The_Samurai	Radio Towers (IOI22_towers)	C++17	23 / 100	4034 ms	13960 KiB

towers

#include "towers.h"
#include "bits/stdc++.h"
using namespace std;

struct segtree {
    vector<int> tree;
    int size;

    void init(int n) {
        size = 1;
        while (size < n) size *= 2;
        tree.assign(2 * size, 0);
    }

    void upd(int i, int v) {
        i += size;
        tree[i] = max(tree[i], v);
        for (; i > 1; i >>= 1) tree[i >> 1] = max(tree[i], tree[i ^ 1]);
    }

    int get(int l, int r) {
        if (l > r) return 0;
        int res = 0;
        for (l += size, r += size + 1; l < r; l >>= 1, r >>= 1) {
            if (l & 1) res = max(res, tree[l++]);
            if (r & 1) res = max(res, tree[--r]);
        }
        return res;
    }
};

int n;
vector<int> a;
segtree sg1, sg2;

void init(int _n, std::vector<int> _a) {
    n = _n;
    a = _a;
    
}

int max_towers(int l, int r, int d) {
    vector<int> all, v;
    for (int i = 0; i < n; i++) {
        all.emplace_back(a[i]);
        all.emplace_back(a[i] - d);
        all.emplace_back(a[i] + d);
    }
    sort(all.begin(), all.end());
    for (int i = 0; i < all.size(); i++) {
        if (i > 0 and all[i] == all[i - 1]) continue;
        v.emplace_back(all[i]);
    }
    int z = all.size();
    sg1.init(z + 1); sg2.init(z + 1);


    int ans = 0;
    for (int i = l; i <= r; i++) {
        int pos = lower_bound(v.begin(), v.end(), a[i]) - v.begin();
        int pos2 = lower_bound(v.begin(), v.end(), a[i] + d) - v.begin();
        ans = max(ans, sg1.get(pos2, z) + 1);
        sg2.upd(pos2, sg1.get(pos2, z) + 1);

        sg1.upd(pos, sg2.get(0, pos));
    }

    return ans;
}

Compilation message (stderr)

towers.cpp: In function 'int max_towers(int, int, int)':
towers.cpp:50:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   50 |     for (int i = 0; i < all.size(); i++) {
      |                     ~~^~~~~~~~~~~~

• Subtask 1: 0 / 4
• Subtask 2: 11 / 11
• Subtask 3: 12 / 12
• Subtask 4: 0 / 14
• Subtask 5: 0 / 17
• Subtask 6: 0 / 19
• Subtask 7: 0 / 23