Submission #157343

#	Time	Username	Problem	Language	Result	Execution time	Memory
157343		qkxwsm	Rectangles (IOI19_rect)	C++14	72 / 100	3547 ms	1048580 KiB

rect

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

using namespace std;

template<class T, class U>
void ckmin(T &a, U b)
{
	if (a > b) a = b;
}

template<class T, class U>
void ckmax(T &a, U b)
{
	if (a < b) a = b;
}

#define y1 qkx
#define y2 wsm
#define MP make_pair
#define PB push_back
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define FOR(i, a, b) for (auto i = (a); i < (b); i++)
#define FORD(i, a, b) for (auto i = (a) - 1; i >= (b); i--)
#define SZ(x) ((int) (x).size())
#define ALL(x) (x).begin(), (x).end()
#define INF 1000000007
#define MAXN 2513

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<pii> vpi;
typedef vector<pll> vpl;

int N, M;
vector<vi> grid;
int rt[MAXN][MAXN], dn[MAXN][MAXN], lt[MAXN][MAXN], up[MAXN][MAXN];
vi ev[MAXN][MAXN], eh[MAXN][MAXN];
vi dv[MAXN][MAXN], dh[MAXN][MAXN];
ll ans;

ll count_rectangles(vector<vi> a)
{
	N = SZ(a); M = SZ(a[0]); grid = a;
	//BE SUPER CAREFUL ABOUT EQUALITY CASE.
	//for each guy, find the next guy right of it that's greater th an it.
	//ok fix the starting column #.
	FOR(i, 0, N)
	{
		vpi cand; cand.PB({INF, M + 1});
		FORD(j, M, 0)
		{
			while(cand.back().fi < grid[i][j]) cand.pop_back();
			rt[i][j] = cand.back().se;
			cand.PB({grid[i][j], j});
		}
		cand.clear(); cand.PB({INF, -2});
		FOR(j, 0, M)
		{
			while(cand.back().fi < grid[i][j]) cand.pop_back();
			lt[i][j] = cand.back().se;
			cand.PB({grid[i][j], j});
		}
	}
	FOR(i, 0, M)
	{
		vpi cand; cand.PB({INF, N + 1});
		FORD(j, N, 0)
		{
			while(cand.back().fi < grid[j][i]) cand.pop_back();
			dn[j][i] = cand.back().se;
			cand.PB({grid[j][i], j});
		}
		cand.clear(); cand.PB({INF, -2});
		FOR(j, 0, N)
		{
			while(cand.back().fi < grid[j][i]) cand.pop_back();
			up[j][i] = cand.back().se;
			cand.PB({grid[j][i], j});
		}
	}
	FOR(i, 0, N)
	{
		FOR(j, 0, M)
		{
			// cerr << "POS " << i << ' ' << j << endl;
			int idx = lt[i][j];
			// cerr << idx << ' ';
			if (idx >= 0 & idx != j - 1)
			{
				eh[i][idx + 1].PB(j - 1);
			}
			idx = rt[i][j];
			// cerr << idx << ' ';
			if (idx < M && idx != j + 1)
			{
				eh[i][j + 1].PB(idx - 1);
			}
			idx = up[i][j];
			// cerr << idx << ' ';
			if (idx >= 0 && idx != i - 1)
			{
				ev[idx + 1][j].PB(i - 1);
			}
			idx = dn[i][j];
			// cerr << idx << endl;
			if (idx < N && idx != i + 1)
			{
				ev[i + 1][j].PB(idx - 1);
			}
		}
	}
	FOR(i, 0, N)
	{
		FOR(j, 0, M)
		{
			sort(ALL(ev[i][j])); ev[i][j].erase(unique(ALL(ev[i][j])), ev[i][j].end());
			sort(ALL(eh[i][j])); eh[i][j].erase(unique(ALL(eh[i][j])), eh[i][j].end());
			dv[i][j].resize(SZ(ev[i][j]));
			dh[i][j].resize(SZ(eh[i][j]));
			// cerr << "EDGES FROM " << i << ',' << j << endl;
			// cerr << "VERTICAL\n";
			// for (int x : ev[i][j])
			// {
			// 	cerr << x << ' ' << j << endl;
			// }
			// cerr << "HORIZONTAL\n";
			// for (int y : eh[i][j])
			// {
			// 	cerr << i << ' ' << y << endl;
			// }
		}
	}
	FOR(i, 0, N)
	{
		FORD(j, M, 0)
		{
			int idx = 0;
			FOR(k, 0, SZ(ev[i][j]))
			{
				dv[i][j][k] = j;
				int x = ev[i][j][k];
				while(idx < SZ(ev[i][j + 1]) && ev[i][j + 1][idx] < x) idx++;
				if (idx >= SZ(ev[i][j + 1]) || ev[i][j + 1][idx] != x) continue;
				dv[i][j][k] = dv[i][j + 1][idx];
			}
		}
	}
	FOR(i, 0, M)
	{
		FORD(j, N, 0)
		{
			int idx = 0;
			FOR(k, 0, SZ(eh[j][i]))
			{
				dh[j][i][k] = j;
				int y = eh[j][i][k];
				while(idx < SZ(eh[j + 1][i]) && eh[j + 1][i][idx] < y) idx++;
				if (idx >= SZ(eh[j + 1][i]) || eh[j + 1][i][idx] != y) continue;
				dh[j][i][k] = dh[j + 1][i][idx];
			}
		}
	}
	FOR(i, 1, N - 1)
	{
		FOR(j, 1, M - 1)
		{
			FOR(k, 0, SZ(ev[i][j]))
			{
				int x = ev[i][j][k];
				if (x >= N - 1) continue;
				FOR(m, 0, SZ(eh[i][j]))
				{
					int y = eh[i][j][m];
					if (y >= M - 1) continue;
					if (dh[i][j][m] >= x && dv[i][j][k] >= y)
					{
						// cout << i << ',' << j << "=>" << x << ',' << y << endl;
						ans++;
					}
				}
			}
		}
	}
	//for each horizontal segment, see how far up it can go.
	//for each vertical segment, see how far left it can go
	//ok lol idk
	return ans;
}

Compilation message (stderr)

rect.cpp: In function 'll count_rectangles(std::vector<std::vector<int> >)':
rect.cpp:96:12: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
    if (idx >= 0 & idx != j - 1)
        ~~~~^~~~

• Subtask 1: 8 / 8
• Subtask 2: 7 / 7
• Subtask 3: 12 / 12
• Subtask 4: 22 / 22
• Subtask 5: 10 / 10
• Subtask 6: 13 / 13
• Subtask 7: 0 / 28