Submission #1206377

#	Time	Username	Problem	Language	Result	Execution time	Memory
1206377		countless	Rectangles (IOI19_rect)	C++20	Compilation error	0 ms	0 KiB

rect

#include "rect.h"
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef long double ld;

const ll MOD = 998244353;
// const ll INF = 1e18;
const int INF = 5e3;
const ld EPS = 1e-12;

#define endl "\n"
#define sp <<" "<<
#define REP(i, a, b) for(ll i = a; i < b; i++)
#define dbg(x) cout << #x << " = " << x << endl
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define fast_io() ios_base::sync_with_stdio(false); cin.tie(NULL)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define sz(x) ((ll)(x).size())

struct custom_hash {
	static uint64_t splitmix64(uint64_t x) {
		// http://xorshift.di.unimi.it/splitmix64.c
		x += 0x9e3779b97f4a7c15;
		x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
		x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
		return x ^ (x >> 31);
	}

	size_t operator()(uint64_t x) const {
		static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
		return splitmix64(x + FIXED_RANDOM);
	}
};

struct pair_hash {
	size_t operator()(const pair<int, int> &p) const {
		size_t h1 = custom_hash{}(p.first);
		size_t h2 = custom_hash{}(p.second);
		return h1 ^ (h2 << 1);
	}
};

struct rect_hash {
	size_t operator()(const pair<pair<int, int>, pair<int, int>> &p) const {
		size_t h1 = pair_hash{}(p.first);
		size_t h2 = pair_hash{}(p.second);
		return h1 ^ (h2 << 1);
	}
};

using rect = pair<pair<int, int>, pair<int, int>>;

template <typename Key, typename Value>
using hash_map = unordered_map<Key, Value, custom_hash>;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
// uniform_int_distribution<int>(a, b)(rng);
// shuffle(all(a), rng);

struct Sparse {
    vector<vector<int>> table;
    int size, LOGN;

    Sparse(vector<int> &data, int n) {
        size = n;

        LOGN = log2(size) + 1;

        table = vector<vector<int>>(size, vector<int>(LOGN, 0));

        build(data);
    }

    // handle merge here
    int merge(int left, int right) {
        return max(left, right);
    }

    void build(vector<int> &data) {
        for (int i = 0; i < size; i++) {
            table[i][0] = data[i];
        }

        for (int j = 1; j < LOGN; j++) {
            for (int i = 0; i + (1 << j) - 1 < size; i++) {
                table[i][j] = merge(table[i][j-1], table[i+(1 << (j-1))][j-1]);
            }
        }
    }

    int query(int l, int r) {
        int sz = r - l + 1;
        int j = log2(sz);

        return merge(table[l][j], table[r-(1<<(j))+1][j]);
    }
};

ll count_rectangles(vector<vector<int>> a) {
	ll n = a.size(), m = a[0].size();
	ll ans = 0;

	vector<vector<pair<int, int>>> brows(n, vector<pair<int, int>>(m, mp(-INF, INF))), bcols;
	bcols = brows;
	vector<Sparse> rows, cols;

	// O(n lg m)
	REP(i, 0, n) {
		rows.push_back(Sparse(a[i], m));
	}

	// O(m lg n)
	REP(i, 0, m) {
		vector<int> col(n);
		REP(j, 0, n) {
			col[j] = a[j][i];
		}

		cols.push_back(Sparse(col, n));
	}

	stack<int> st;

	// O(nm)
	REP(i, 0, n) {
		REP(j, 0, m) {
			while (!st.empty() and a[i][st.top()] <= a[i][j]) {
				st.pop();
			}

			if (!st.empty()) {
				brows[i][j].first = st.top();
			}

			st.push(j);
		}

		while (!st.empty()) st.pop();

		for (int j = m-1; j >= 0; j--) {
			while (!st.empty() and a[i][st.top()] <= a[i][j]) {
				st.pop();
			}

			if (!st.empty()) {
				brows[i][j].second = st.top();
			}

			st.push(j);
		}
	}

	while (!st.empty()) st.pop();

	REP(i, 0, m) {
		REP(j, 0, n) {
			while (!st.empty() and a[st.top()][i] <= a[j][i]) {
				st.pop();
			}

			if (!st.empty()) {
				bcols[j][i].first = st.top();
			}

			st.push(j);
		}

		while (!st.empty()) st.pop();

		for (int j = n-1; j >= 0; j--) {
			while (!st.empty() and a[st.top()][i] <= a[j][i]) {
				st.pop();
			}

			if (!st.empty()) {
				bcols[j][i].second = st.top();
			}

			st.push(j);
		}
	}
	
	auto in = [&](int x, int y) -> bool {
		return (0 < x and x < n-1 and 0 < y and y < m-1);
	};

	// O(n + m)
	unordered_map<rect, bool, rect_hash> vis;
	auto checkRect = [&](int x, int y, int xx, int yy) -> int {
		if (!in(x,y) or !in(xx, yy)) return 0;

		if (x > xx) swap(x, xx);
		if (y > yy) swap(y, yy);

		if (vis[{{x, y}, {xx, yy}}]) return 0;

		vis[{{x, y}, {xx, yy}}] = true;

		int cap;

		REP(i, x, xx+1) {
			cap = min(a[i][y-1], a[i][yy+1]);
			if (rows[i].query(y, yy) >= cap) {
				return 0;
			}
		}

		REP(i, y, yy+1) {
			cap = min(a[x-1][i], a[xx+1][i]);
			if (cols[i].query(x, xx) >= cap) {
				return 0;
			}
		}

		return 1;
	};

	// O(nm (n+m))
	REP(i, 1, n-1) {
		REP(j, 1, m-1) {
			if (brows[i][j].first == -INF or brows[i][j].second == INF or bcols[i][j].first == -INF or bcols[i][j].second == INF)
				continue;
			ans += checkRect(bcols[i][j].first+1, brows[i][j].first+1, bcols[i][j].second-1, brows[i][j].second-1);
		}
	}

	return ans;
}

int main() {
	int n, m; cin >> n >> m;
	vector<vector<int>> a(n, vector<int>(m));
	REP(i, 0, n) {
		REP(j, 0, m) {
			cin >> a[i][j];
		}
	}

	cout << count_rectangles(a) << endl;
}

Compilation message (stderr)

/usr/bin/ld: /tmp/cctWNVSx.o: in function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'; /tmp/ccFZs94R.o:rect.cpp:(.text.startup+0x0): first defined here
collect2: error: ld returned 1 exit status