제출 #925908

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
925908		boris_mihov	Monochrome Points (JOI20_monochrome)	C++17	35 / 100	2054 ms	7128 KiB

monochrome

#include <algorithm>
#include <iostream>
#include <numeric>
#include <cassert>
#include <cstring>
#include <vector>
#include <queue>
#include <stack>
#include <set>

typedef long long llong;
const int MAXN = 400000 + 10;
const int INF  = 2e9;

int n;
int w[MAXN];
int b[MAXN];
char s[MAXN];
int f[MAXN];
int fPrim[MAXN];
std::vector <std::pair <int,int>> v;

int solveFor(int k)
{
    v.clear();
    for (int i = 1 ; i <= n ; ++i)
    {
        v.push_back({std::min(w[i], b[(i + k - 1) % n + 1]), std::max(w[i], b[(i + k - 1) % n + 1])});
    }

    int res = 0;
    std::sort(v.begin(), v.end());
    for (int i = 0 ; i < n ; ++i)
    {
        for (int j = i + 1 ; j < n ; ++j)
        {
            res += (v[j].first < v[i].second && v[i].second < v[j].second);
        }
    }

    return res;
}

void solve()
{
    int cntW = 1;
    int cntB = 1;
    for (int i = 1 ; i <= 2 * n ; ++i)
    {
        if (s[i] == s[1]) w[cntW++] = i;
        else b[cntB++] = i;
    }

    int l = 0, r = n - 1, mid;
    while (l < r - 1)
    {
        mid = (l + r) / 2;
        if (solveFor(mid) - solveFor(mid - 1) >= 0) l = mid;
        else r = mid;
    }

    int res = std::max(solveFor(0), solveFor(n - 1));
    std::cout << std::max(res, solveFor(l)) << '\n';
}

void input()
{
    std::cin >> n;
    std::cin >> s + 1;
}

void fastIOI()
{
    std::ios_base :: sync_with_stdio(0);
    std::cout.tie(nullptr);
    std::cin.tie(nullptr);
}   

int main()
{
    fastIOI();
    input();
    solve();

    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

monochrome.cpp: In function 'void input()':
monochrome.cpp:69:19: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   69 |     std::cin >> s + 1;
      |                 ~~^~~

• Subtask 1: 4 / 4
• Subtask 2: 21 / 21
• Subtask 3: 10 / 10
• Subtask 4: 0 / 65