Submission #793833

#	Time	Username	Problem	Language	Result	Execution time	Memory
793833		finn__	Mutating DNA (IOI21_dna)	C++17	100 / 100	78 ms	6344 KiB

dna

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

template <typename T>
struct fenwick_tree
{
    vector<T> t;

    fenwick_tree() {}

    fenwick_tree(size_t n) { t.resize(n); }

    void update(int64_t i, T x)
    {
        ++i;
        while (i <= t.size())
            t[i - 1] += x, i += i & -i;
    }

    T range_sum(int64_t i, int64_t j)
    {
        T x = 0;
        ++j;
        while (j)
            x += t[j - 1], j -= j & -j;
        while (i)
            x -= t[i - 1], i -= i & -i;
        return x;
    }
};

constexpr size_t N = 100000;

vector<uint8_t> a, b;
fenwick_tree<int> c[3][3];

uint8_t conv(char c) { return c == 'A' ? 0 : (c == 'C' ? 1 : 2); }

void init(string a_, string b_)
{
    size_t n = a_.size();
    a.resize(n);
    b.resize(n);
    for (size_t i = 0; i < n; ++i)
        a[i] = conv(a_[i]), b[i] = conv(b_[i]);

    for (size_t i = 0; i < 3; ++i)
        for (size_t j = 0; j < 3; ++j)
            c[i][j] = fenwick_tree<int>(n);

    for (size_t i = 0; i < n; ++i)
        c[a[i]][b[i]].update(i, 1);
}

bool equal_set_in_range(size_t i, size_t j)
{
    return c[0][0].range_sum(i, j) + c[0][1].range_sum(i, j) + c[0][2].range_sum(i, j) ==
               c[0][0].range_sum(i, j) + c[1][0].range_sum(i, j) + c[2][0].range_sum(i, j) &&
           c[1][0].range_sum(i, j) + c[1][1].range_sum(i, j) + c[1][2].range_sum(i, j) ==
               c[0][1].range_sum(i, j) + c[1][1].range_sum(i, j) + c[2][1].range_sum(i, j) &&
           c[2][0].range_sum(i, j) + c[2][1].range_sum(i, j) + c[2][2].range_sum(i, j) ==
               c[0][2].range_sum(i, j) + c[1][2].range_sum(i, j) + c[2][2].range_sum(i, j);
}

int get_distance(int x, int y)
{
    if (!equal_set_in_range(x, y))
        return -1;

    int ans = 0, num_matched = 0;

    num_matched += c[0][0].range_sum(x, y) + c[1][1].range_sum(x, y) + c[2][2].range_sum(x, y);
    for (size_t i = 0; i < 3; ++i)
        for (size_t j = i + 1; j < 3; ++j)
        {
            int count = min(c[i][j].range_sum(x, y), c[j][i].range_sum(x, y));
            ans += count;
            num_matched += count << 1;
        }

    return ans + ((y - x + 1 - num_matched) / 3) * 2;
}

Compilation message (stderr)

dna.cpp: In instantiation of 'void fenwick_tree<T>::update(int64_t, T) [with T = int; int64_t = long int]':
dna.cpp:53:34:   required from here
dna.cpp:17:18: warning: comparison of integer expressions of different signedness: 'int64_t' {aka 'long int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   17 |         while (i <= t.size())
      |                ~~^~~~~~~~~~~

• Subtask 1: 21 / 21
• Subtask 2: 22 / 22
• Subtask 3: 13 / 13
• Subtask 4: 28 / 28
• Subtask 5: 16 / 16