Submission #551493

#	Time	Username	Problem	Language	Result	Execution time	Memory
551493		PiejanVDC	Rectangles (IOI19_rect)	C++17	50 / 100	5081 ms	74100 KiB

rect

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

long long count_rectangles(vector<vector<int>> v) {
    long long ans = 0;
    const int n = (int)v.size();
    const int m = (int)v[0].size();

    if(n < 3 || m < 3)
        return 0LL;

    bool ok = 1;
    for(int i = 0 ; i < n ; i++)
        for(int j = 0 ; j < m ; j++)
            if(v[i][j] > 1)
                ok = 0;

    if(ok) {
        vector<vector<int>>sum(n+1, vector<int>(m+1,0));
        for(int i = 1 ; i <= n ; i++) {
            for(int j = 1 ; j <= m ; j++) {
                sum[i][j] = sum[i][j-1] + sum[i-1][j] - sum[i-1][j-1] + v[i-1][j-1];
            }
        }

        auto get = [&] (int x1, int y1, int x2, int y2) -> int {
            return sum[x1][y1] - sum[x2-1][y1] - sum[x1][y2-1] + sum[x2-1][y2-1];
        };

        for(int i = 1 ; i < n-1 ; i++) {
            for(int j = 1 ; j < m-1 ; j++) {
                if(v[i][j] == 0 && v[i][j+1] == 1) {
                    int l = 1, r = i, f, s;
                    while(l <= r) {
                        int mid = (l+r)/2;
                        if(get(i+1, j+1, mid+1, j+1) == 0)
                            f = mid, r = mid-1;
                        else
                            l = mid+1;
                    }
                    l = 1, r = j;
                    while(l <= r) {
                        int mid = (l+r)/2;
                        if(get(i+1, j+1, i+1, mid+1) == 0)
                            s = mid, r = mid-1;
                        else
                            l = mid+1;
                    }
                    if(get(i+1, j+1, f+1, s+1) != 0)
                        continue;
                    if(get(i+1, j+2, f+1, j+2) == i - f + 1 && get(i+2, j+1, i+2, s+1) == j - s + 1 && get(i+1, s, f+1, s) == i - f + 1 && get(f, j+1, f, s+1) == j - s + 1) {
                        ans++;
                    }
                }
            }
        }
        return ans;
    }

    for(int i = 1 ; i < n-1 ; i++) {
        for(int j = 1 ; j < m-1 ; j++) {
            for(int ii = i ; ii < n-1 ; ii++) {
                for(int jj = j ; jj < m-1 ; jj++) {
                    ok = 1;

                    for(int k = i ; k <= ii && ok ; k++) {
                        for(int l = j ; l <= jj ; l++) {
                            if(v[k][l] >= v[i-1][l] || v[k][l] >= v[ii+1][l] || v[k][l] >= v[k][j-1] || v[k][l] >= v[k][jj+1]) {
                                ok = 0;
                                break;
                            }
                        }
                    }
                    ans += ok;
                }
            }
        }
    }

    return ans;

}

/*

6 5
4 8 7 5 6
7 4 10 3 5
9 7 20 14 2
9 14 7 3 6
5 7 5 2 7
4 5 13 5 6

#include <cstdio>
#include <unistd.h>
#include <cassert>
#include <string>

using namespace std;

class InputReader {
private:
	static const int SIZE = 4096;

	int inputFileDescriptor;
	char buf[SIZE];
	int curChar;
	int numChars;

public:

	inline InputReader(int _inputFileDescriptor):
		inputFileDescriptor(_inputFileDescriptor),
		curChar(0),
		numChars(0) {
	}

	inline void close() {
		::close(inputFileDescriptor);
	}

	inline char read() {
		assert(numChars != -1);
		if (curChar >= numChars) {
			curChar = 0;
			numChars = ::read(inputFileDescriptor, buf, SIZE);
			if (numChars == -1)
				return -1;
		}
		return buf[curChar++];
	}

	inline int readInt() {
		int c = eatWhite();
		int sgn = 1;
		if (c == '-') {
			sgn = -1;
			c = read();
		}
		int res = 0;
		do {
			assert(c >= '0' && c <= '9');
			res *= 10;
			res += c - '0';
			c = read();
		} while (!isSpaceChar(c));
		return res * sgn;
	}

	inline string readString() {
		char c = eatWhite();
		string res;
		do {
			res += c;
			c = read();
		} while (!isSpaceChar(c));
		return res;
	}

	inline string readLine() {
		string res;
		while (true) {
			char c = read();
			if (c == '\n' || c == '\r' || c == -1)
				break;
			res += c;
		}
		return res;
	}

	inline char eatWhite() {
		char c = read();
		while (isSpaceChar(c))
			c = read();
		return c;
	}

	static inline bool isSpaceChar(char c) {
		return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
	}
};


int main() {
	InputReader inputReader(STDIN_FILENO);
	int n, m;
	cin>>n>>m;
	vector<vector<int>> a(n, vector<int>(m));
	for (int i = 0; i < n; i++)	{
		for (int j = 0; j < m; j++) {
			cin>>a[i][j];
		}
	}

	long long result = count_rectangles(a);

	printf("%lld\n", result);
	return 0;
}

*/

Compilation message (stderr)

rect.cpp: In function 'long long int count_rectangles(std::vector<std::vector<int> >)':
rect.cpp:52:93: warning: 's' may be used uninitialized in this function [-Wmaybe-uninitialized]
   52 |                     if(get(i+1, j+2, f+1, j+2) == i - f + 1 && get(i+2, j+1, i+2, s+1) == j - s + 1 && get(i+1, s, f+1, s) == i - f + 1 && get(f, j+1, f, s+1) == j - s + 1) {
      |                                                                                           ~~^~~
rect.cpp:52:53: warning: 'f' may be used uninitialized in this function [-Wmaybe-uninitialized]
   52 |                     if(get(i+1, j+2, f+1, j+2) == i - f + 1 && get(i+2, j+1, i+2, s+1) == j - s + 1 && get(i+1, s, f+1, s) == i - f + 1 && get(f, j+1, f, s+1) == j - s + 1) {
      |                                                   ~~^~~

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