Submission #298936

#	Time	Username	Problem	Language	Result	Execution time	Memory
298936		toloraia	Monochrome Points (JOI20_monochrome)	C++14	0 / 100	1 ms	384 KiB

monochrome

#include <bits/stdc++.h>
#define F first
#define S second
#define mp make_pair
#define pb push_back
//#define ll __int128
#define ll long long
#define int long long
#define LEFT(a) ((a)<<1)
#define RIGHT(a) (LEFT(a) + 1)
#define MID(a,b) ((a+b)>>1)
#define MAX(a,b) ((a)>(b)?(a):(b))
#define MIN(a,b) ((a)<(b)?(a):(b))
#define y1 y122
/*
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimization ("unroll-loops")
/*
#pragma GCC optimize ("O3")
#pragma GCC optimize("Ofast")

#pragma GCC target("avx2,fma")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC target ("avx2")
#pragma GCC optimization ("unroll-loops")

#pragma comment(linker, "/STACK: 20000000005")
*/

using namespace std;

const int N = 200005;

int n;
int F[N];

void upd (int x){
    for (; x <= n; x += x&-x)
        F[x]++;
}

int dat (int x){
    int ans = 0;
    for (; x > 0; x &= x-1)
        ans += F[x];
    return ans;
}

int ANS, ans, a[N];
string S;
vector < int > V[2];


main()
{
    //freopen ("in.in", "r", stdin);freopen ("out.out", "w", stdout);
    ios_base::sync_with_stdio(0);
    cin >> n >> S;
    S = S + S;
    for (int st = 0; st < n*2; st+=n){
        for (int i = 1; i <= n; i++){
            char ch=S[i+st-1];
            if (ch == 'B')
                a[i] = 1;
            else
                a[i] = 0;
        }
        for (int i = 1; i <= n; i++){
            char ch = S[i+st+n-1];
            if (ch == 'W')
                V[1].pb (i);
            else
                V[0].pb (i);
        }
        for (int i = n; i >= 1; i--){
            int x = V[a[i]].back();
            V[a[i]].pop_back ();
            ans += dat (n) - dat (x);
            upd (x);
        }
        ANS = max (ans, ANS);
        ans = 0;
        for (int i = 1; i <= n; i++)
            F[i] = 0;
        V[0].clear();
        V[1].clear();
    }
    cout << ANS << endl;
}

Compilation message (stderr)

monochrome.cpp:19:1: warning: "/*" within comment [-Wcomment]
   19 | /*
      |  
monochrome.cpp:55:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   55 | main()
      |      ^

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