Submission #918218

#	Time	Username	Problem	Language	Result	Execution time	Memory
918218		devkudawla	Lightning Rod (NOI18_lightningrod)	C++17	66 / 100	2043 ms	262144 KiB

Main

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef tree<long long, null_type, less<long long>, rb_tree_tag, tree_order_statistics_node_update> ordered_set; // find_by_order(it return an iterator input is a value), order_of_key(input is index)
typedef tree<long long, null_type, less_equal<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_multiset;
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")

template <class T>
void Distinct(T &v, bool sorting = true)
{
    if (sorting)
        sort(begin(v), end(v));
    v.resize(unique(begin(v), end(v)) - begin(v));
}
const int BUF_SZ = 1 << 15;

inline namespace Input
{
    char buf[BUF_SZ];
    int pos;
    int len;
    char next_char()
    {
        if (pos == len)
        {
            pos = 0;
            len = (int)fread(buf, 1, BUF_SZ, stdin);
            if (!len)
            {
                return EOF;
            }
        }
        return buf[pos++];
    }

    int read_int()
    {
        int x;
        char ch;
        int sgn = 1;
        while (!isdigit(ch = next_char()))
        {
            if (ch == '-')
            {
                sgn *= -1;
            }
        }
        x = ch - '0';
        while (isdigit(ch = next_char()))
        {
            x = x * 10 + (ch - '0');
        }
        return x * sgn;
    }
} // namespace Input
inline namespace Output
{
    char buf[BUF_SZ];
    int pos;

    void flush_out()
    {
        fwrite(buf, 1, pos, stdout);
        pos = 0;
    }

    void write_char(char c)
    {
        if (pos == BUF_SZ)
        {
            flush_out();
        }
        buf[pos++] = c;
    }

    void write_int(int x)
    {
        static char num_buf[100];
        if (x < 0)
        {
            write_char('-');
            x *= -1;
        }
        int len = 0;
        for (; x >= 10; x /= 10)
        {
            num_buf[len++] = (char)('0' + (x % 10));
        }
        write_char((char)('0' + x));
        while (len)
        {
            write_char(num_buf[--len]);
        }
        write_char('\n');
    }

    // auto-flush output when program exits
    void init_output() { assert(atexit(flush_out) == 0); }
} // namespace Output

const int sz = 10000010;
const int sz1 = 10000010;
int Fenwick[sz] = {0};
int long Fenwick1[sz1] = {0};

unordered_map<long long int, int> D1, D2;

// 1 BASED INDEXING
// ALWAYS DECLARE FENWICK TREE GLOBALLY
struct fenwicktree
{
    int n;
    vector<int> v;
    fenwicktree(vector<int> A)
    {
        v.resize(A.size() + 1, 0);
        n = A.size();
        for (int i = 0; i < A.size(); i++)
            Add(i + 1, A[i]);
    }
    int Sum(int i)
    {
        int answer = 0;
        for (; i > 0; i -= (i & (-i)))
            answer += Fenwick[i];
        return answer;
    }
    void Add(int i, int x)
    {
        v[i] += x;
        for (; i <= n; i += (i & (-i)))
            Fenwick[i] += x;
    }
    void Replace(int i, int x)
    {
        int y = v[i];
        v[i] = x;
        for (; i <= n; i += (i & (-i)))
            Fenwick[i] += x - y;
    }
    long long RangeSum(int l, int r)
    {
        return Sum(r) - Sum(l - 1);
    }
};

// 1 BASED INDEXING
// ALWAYS DECLARE FENWICK TREE GLOBALLY
struct fenwicktree1
{
    int n;
    vector<int> v;
    fenwicktree1(vector<int> A)
    {
        v.resize(A.size() + 1, 0);
        n = A.size();
        for (int i = 0; i < A.size(); i++)
            Add(i + 1, A[i]);
    }
    int Sum(int i)
    {
        int answer = 0;
        for (; i > 0; i -= (i & (-i)))
            answer += Fenwick1[i];
        return answer;
    }
    void Add(int i, int x)
    {
        v[i] += x;
        for (; i <= n; i += (i & (-i)))
            Fenwick1[i] += x;
    }
    void Replace(int i, int x)
    {
        int y = v[i];
        v[i] = x;
        for (; i <= n; i += (i & (-i)))
            Fenwick1[i] += x - y;
    }
    long long RangeSum(int l, int r)
    {
        return Sum(r) - Sum(l - 1);
    }
};
//----------------------------------------------------
void solve()
{
    int n;
    n = read_int();
    vector<pair<int, int>> v(n);
    for (int i = 0; i < n; i++)
    {
        int a, b;
        a = read_int();
        b = read_int();
        v[i] = {b, a};
    }
    sort(begin(v), end(v));
    reverse(begin(v), end(v));
    int c1, c2;
    {
        vector<long long> a;
        for (int i = 0; i < n; i++)
            a.push_back(v[i].second - v[i].first);
        Distinct(a);
        for (int i = 0; i < a.size(); i++)
            D1[a[i]] = i + 1;
        c1 = a.size();
        a.clear();
        for (int i = 0; i < n; i++)
            a.push_back(v[i].second + v[i].first);
        Distinct(a);
        c2 = a.size();
        for (int i = 0; i < a.size(); i++)
            D2[a[i]] = i + 1;
    }
    fenwicktree a(vector<int>(c1 + 5, 0));
    fenwicktree1 b(vector<int>(c2 + 5, 0));
    int answer = 0;
    for (int i = 0; i < n; i++)
    {
        int d1 = v[i].second - v[i].first;
        int d2 = v[i].second + v[i].first;
        int p1 = a.RangeSum(1, D1[d1]);
        int p2 = b.RangeSum(D2[d2], c2);
        if (p1 + p2 - answer > 0)
            continue;
        answer++;
        a.Add(D1[d1], 1);
        b.Add(D2[d2], 1);
    }
    write_int(answer);
}
//----------------------------------------------------
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    init_output();

    solve();

    return 0;
}
//----------------------------------------------------

Compilation message (stderr)

lightningrod.cpp: In constructor 'fenwicktree::fenwicktree(std::vector<int>)':
lightningrod.cpp:121:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  121 |         for (int i = 0; i < A.size(); i++)
      |                         ~~^~~~~~~~~~
lightningrod.cpp: In constructor 'fenwicktree1::fenwicktree1(std::vector<int>)':
lightningrod.cpp:160:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  160 |         for (int i = 0; i < A.size(); i++)
      |                         ~~^~~~~~~~~~
lightningrod.cpp: In function 'void solve()':
lightningrod.cpp:209:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  209 |         for (int i = 0; i < a.size(); i++)
      |                         ~~^~~~~~~~~~
lightningrod.cpp:217:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  217 |         for (int i = 0; i < a.size(); i++)
      |                         ~~^~~~~~~~~~

• Subtask 1: 0 / 4
• Subtask 2: 7 / 7
• Subtask 3: 12 / 12
• Subtask 4: 21 / 21
• Subtask 5: 26 / 26
• Subtask 6: 0 / 10
• Subtask 7: 0 / 20