Submission #306852

#	Time	Username	Problem	Language	Result	Execution time	Memory
306852		joylintp	Handcrafted Gift (IOI20_gift)	C++14	100 / 100	265 ms	17632 KiB

gift

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

int construct (int n, int r, vector<int> a, vector<int> b, vector<int> x)
{
    vector<pair<int, int>> v;
    for (int i = 0; i < r; i++)
        if (x[i] == 1)
            v.push_back({a[i], b[i]});
    sort(v.begin(), v.end());

    vector<pair<int, int>> same;
    for (int i = 0; i < v.size(); i++)
        if (same.empty())
            same.push_back(v[i]);
        else if (same.back().second + 1 >= v[i].first)
            same.back().second = max(same.back().second, v[i].second);
        else
            same.push_back(v[i]);

    string s;
    for (int i = 0; i < same.size(); i++)
    {
        for (int j = (i == 0 ? 0 : same[i - 1].second + 1); j <= same[i].first; j++)
            if (s.empty())
                s += 'R';
            else if (s.back() == 'R')
                s += 'B';
            else
                s += 'R';

        for (int j = same[i].first + 1; j <= same[i].second; j++)
            if (s.empty())
                s += 'R';
            else
                s += s.back();
    }

    for (int i = (s.empty() ? 0 : same.back().second + 1); i < n; i++)
        if (s.empty())
                s += 'R';
        else if (s.back() == 'R')
            s += 'B';
        else
            s += 'R';

    vector<int> v2;
    for (auto p : same)
        v2.push_back(p.first), v2.push_back(p.second);

    for (int i = 0; i < r; i++)
    {
        if (x[i] == 1)
            continue;

        if (a[i] == b[i])
            return 0;

        int pos = upper_bound(v2.begin(), v2.end(), a[i]) - v2.begin() - 1;
        if (pos != -1 && pos % 2 == 0 && b[i] <= v2[pos + 1])
            return 0;
    }

    craft(s);
    return 1;
}

Compilation message (stderr)

gift.cpp: In function 'int construct(int, int, std::vector<int>, std::vector<int>, std::vector<int>)':
gift.cpp:14:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   14 |     for (int i = 0; i < v.size(); i++)
      |                     ~~^~~~~~~~~~
gift.cpp:23:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |     for (int i = 0; i < same.size(); i++)
      |                     ~~^~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 20 / 20
• Subtask 4: 25 / 25
• Subtask 5: 30 / 30