제출 #823518

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
823518		phoenix	Rectangles (IOI19_rect)	C++17	13 / 100	1214 ms	441988 KiB

rect

#include<bits/stdc++.h>
#include "rect.h"

using namespace std;
using ll = long long;

struct FenwickTree {
    vector<int> bit;  // binary indexed tree
    int n;

    FenwickTree(int n) {
        this->n = n;
        bit.assign(n, 0);
    }
    FenwickTree(vector<int> const &a) : FenwickTree(a.size()) {
        for (size_t i = 0; i < a.size(); i++)
            add(i, a[i]);
    }

    int sum(int r) {
        int ret = 0;
        for (; r >= 0; r = (r & (r + 1)) - 1)
            ret += bit[r];
        return ret;
    }

    int sum(int l, int r) {
        return sum(r) - sum(l - 1);
    }

    void add(int idx, int delta) {
        for (; idx < n; idx = idx | (idx + 1))
            bit[idx] += delta;
    }
};

void compress(vector<vector<int>> &a) {
	map<int, int> mp;
	int n = (int)a.size(), m = (int)a[0].size();
	for(int i = 0; i < n; i++) 	
		for(int j = 0; j < m; j++)
		mp[a[i][j]] = 1;
	int k = 0;
	for(auto &c : mp) {
		c.second = k++;
	}
	for(int i = 0; i < n; i++) 
		for(int j = 0; j < m; j++)
			a[i][j] = mp[a[i][j]];
}

// O(nlogn)
vector<pair<int, int>> get_segments(vector<int> a) {
	int n = (int)a.size();

	vector<pair<int, int>> res;
	int rb[n];
	int pre[n] = {};
	for(int i = 0; i < n; i++) 
		pre[i] = (i ? pre[i - 1] : 0) + a[i];
	for(int i = 0; i < n - 1; i++) {
		if(a[i] && !a[i + 1]) {
			int lb = i + 1, rb = n;
			while(rb - lb > 1) {
				int mid = (lb + rb) / 2;
				if(pre[mid] == pre[i]) lb = mid;
				else rb = mid;
			}
			if(rb != n) res.push_back({i + 1, lb});
		}
	}
	return res;	
}

const int N = 2505;

struct segment {
	int l, d;
};

vector<segment> h[N][N], g[N][N];

ll count_rectangles(vector<vector<int>> a) {
	int n = (int)a.size(), m = (int)a[0].size();
	if(n < 3 || m < 3) return 0;
	compress(a);
	for(int i = 0; i < n; i++) {
		vector<pair<int, int>> s = get_segments(a[i]);
		for(auto [l, r] : s) 
			g[i][r].push_back({l, 0});
	}
	for(int i = 0; i < m; i++) {
		vector<int> b;
		for(int j = 0; j < n; j++) 
			b.push_back(a[j][i]);
		vector<pair<int, int>> s = get_segments(b);
		for(auto [l, r] : s) 
			h[r][i].push_back({l, 0});
	}
	for(int i = 0; i < n; i++) {
		int cnt[n] = {};
		bool us[n] = {};
		for(int j = 0; j < m; j++) {
			if(!j) {
				for(auto c : h[i][j]) 
					cnt[c.l]++;
			} else {
				for(auto c : h[i][j])
					us[c.l] = 1;
				for(auto c : h[i][j - 1])
					if(!us[c.l]) cnt[c.l] = 0;
				
				for(auto c : h[i][j]) {
					cnt[c.l]++;
					us[c.l] = 0;
				}
			}
			for(auto &c : h[i][j]) {
				c.d = cnt[c.l];
			}
		}
	}
	for(int i = 0; i < m; i++) {
		int cnt[m] = {};
		bool us[m] = {};
		for(int j = 0; j < n; j++) {
			if(!j) {
				for(auto c : g[j][i]) 
					cnt[c.l]++;
			} else {
				for(auto c : g[j][i]) 
					us[c.l] = 1;
				for(auto c : g[j - 1][i]) 
					if(!us[c.l]) 
						cnt[c.l] = 0;
				for(auto c : g[j][i]) {
					cnt[c.l]++;
					us[c.l] = 0;
				}
			}
			for(auto &c : g[j][i])
				c.d = cnt[c.l];
		}
	}
	ll ans = 0;
	FenwickTree st(n);
	for(int i = 0; i < n; i++) {
		for(int j = 0; j < m; j++) {
			sort(h[i][j].begin(), h[i][j].end(), [](segment x, segment y) {return x.d > y.d;});
			int h_l = 0;
			for(segment cur : g[i][j]) {
				while(h_l < (int)h[i][j].size() && j - h[i][j][h_l].d < cur.l) {
					st.add(h[i][j][h_l++].l, +1);
				} 
				ans += st.sum(i - cur.d + 1, i);
			}
			while(h_l > 0) 
				st.add(h[i][j][--h_l].l, -1);
		}
	}
	return ans;
}

컴파일 시 표준 에러 (stderr) 메시지

rect.cpp: In function 'std::vector<std::pair<int, int> > get_segments(std::vector<int>)':
rect.cpp:57:6: warning: unused variable 'rb' [-Wunused-variable]
   57 |  int rb[n];
      |      ^~

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