Submission #628433

#	Time	Username	Problem	Language	Result	Execution time	Memory
628433		MohamedFaresNebili	Monochrome Points (JOI20_monochrome)	C++14	35 / 100	2091 ms	8468 KiB

monochrome

#include <bits/stdc++.h>

            using namespace std;

            using ll = long long;
            using ld = long double;
            using pi = pair<pair<int, int>, pair<int, int>>;

            #define ff first
            #define ss second
            #define pb push_back
            #define all(x) (x).begin(), (x).end()
            #define lb lower_bound
            #define int ll

            int N, ST[80005]; string S;
            vector<int> A, B;

            int solve(int v) {
                vector<pair<int, int>> P;
                for(int l = 0; l < N; l++)
                    P.push_back({A[l], B[(l + v) % N]});
                int res = 0;
                for(int l = 0; l < N; l++) {
                    for(int i = l + 1; i < N; i++) {
                        int U = P[l].first, V = P[l].second;
                        int X = P[i].first, Y = P[i].second;
                        if(U > V) swap(U, V);
                        if(X > Y) swap(X, Y);
                        if(V < X) continue;
                        if(Y < U) continue;
                        if(U > X && V < Y) continue;
                        if(X > U && Y < V) continue;
                        res++;
                    }
                }
                return res;
            }

            int32_t main() {
                ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
                cin >> N >> S; int res = 0;
                for(int l = 0; l < 2 * N; l++) {
                    if(S[l] == 'B') A.push_back(l);
                    if(S[l] == 'W') B.push_back(l);
                }
                int lo = 0, hi = N - 1;
                while(lo <= hi) {
                    int md = (lo + hi) / 2;
                    int U = solve(md), V = solve(md + 1);
                    if(V > U) { lo = md + 1, res = max(res, V); }
                    else hi = md - 1, res = max(res, U);
                }
                cout << res << "\n";
                return 0;
            }

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