제출 #1190158

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1190158		drakozs	Monochrome Points (JOI20_monochrome)	C++20	35 / 100	2094 ms	10204 KiB

monochrome

#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#pragma GCC optimize("Ofast") 
#pragma GCC optimize("unroll-loops") 
#pragma GCC target("avx,avx2,fma")
using namespace __gnu_pbds;
#define ordered_set tree<pair<int, int>, null_type,less<pair<int, int>>, rb_tree_tag,tree_order_statistics_node_update>
#define ll long long
#define MOD 1000000007
#define MAXN 2e5
#define SIZE 314
#define pb push_back

using namespace std;

ll power(ll a, ll b){
	if (b == 0) return 1;
	ll res = power(a, b / 2);
//	if (b % 2 == 1) return res * res % MOD * a % MOD;
//	return res * res % MOD;
	
	if (b % 2 == 1) return res * res * a;
	return res * res;
}

void update(vector<int> &segTree, int curr, int pos, int l, int r){
	segTree[curr]++;
	if (l == r) return;
	int mid = (r - l) / 2 + l;
	if (pos <= mid){
		update(segTree, curr * 2 + 1, pos, l, mid);
	}
	else{
		update(segTree, curr * 2 + 2, pos, mid + 1, r);
	}
}

int getCount(vector<int> &segTree, int curr, int l, int r, int findL, int findR){
	if (l >= findL && r <= findR) return segTree[curr];
	int mid = (r - l) / 2 + l;
	int ans = 0;
	if (findL <= mid){
		ans += getCount(segTree, curr * 2 + 1, l, mid, findL, findR);
	}
	if (findR > mid){
		ans += getCount(segTree, curr * 2 + 2, mid + 1, r, findL, findR);
	}
	return ans;
}

int getAns(int n, vector<int> &w, vector<int> &b, int k, vector<pair<int, int>> &allPair){
	int curr = 0;
	for (int i = 0; i < n; i++){
		int wPos = w[i], bPos = b[(i + k) % n];
		allPair[i] = {min(wPos, bPos), max(wPos, bPos)};
	}
	sort(allPair.begin(), allPair.end());
	vector<int> segTree(8 * n, 0);
	for (int i = 0; i < n; i++){
		curr += getCount(segTree, 0, 0, 2 * n - 1, allPair[i].first, allPair[i].second);
		update(segTree, 0, allPair[i].second, 0, 2 * n - 1);
	}
	return curr;
}

int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	
	int n;
	cin >> n;
	string s;
	cin >> s;
	vector<int> w(n), b(n);
	vector<pair<int, int>> allPair(n);
	int curW = 0, curB = 0;
	for (int i = 0; i < 2 * n; i++){
		if (s[i] == 'W'){
			w[curW++] = i;
		}
		else{
			b[curB++] = i;
		}
	}
	int ans = 0;
	int left = 0, right = n - 1, mid;
	while(left <= right){
		mid = (right - left) / 2 + left;
		int curr = getAns(n, w, b, mid, allPair);
		int prev = 0;
		if (mid - 1 >= 0){
			prev = getAns(n, w, b, mid - 1, allPair);
		}
		
		ans = max(ans, curr);
		if (curr > prev){
			left = mid + 1;
		}
		else{
			right = mid - 1;
		}
	}
	ans = max(ans, getAns(n, w, b, 0, allPair));
	ans = max(ans, getAns(n, w, b, n - 1, allPair));
	cout << ans << "\n";
	
	
	return 0;
}

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