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// 1072. Flip Columns For Maximum Number of Equal Rows
#include "leetcode.h"
/*
* you are given an 'm x n' binary matrix 'matrix'. you choose any number of
* columns in the matrix and flip every cell in that column (ie. change the
* value of the cell from 0 to 1 or vice versa). return the maximum number of
* rows that have all values equal after some number of flips.
*/
bool rows_equal(int *r1, int *r2, int n) {
for (int i = 0; i < n; i++)
if (r1[i] != r2[i])
return false;
return true;
}
void flip_row(int *row, int *flipped, int numCols) {
for (int i = 0; i < numCols; i++)
flipped[i] = 1 - row[i];
}
int maxEqualRowsAfterFlips(int **matrix, int matrixSize, int *matrixColSize) {
int *flipped = (int *)malloc(matrixColSize[0] * sizeof(int)), ans = 0;
for (int i = 0; i < matrixSize; i++) {
int same_row_cnt = 0;
flip_row(matrix[i], flipped, matrixColSize[0]);
for (int j = 0; j < matrixSize; j++)
if (rows_equal(matrix[i], matrix[j], matrixColSize[0]) ||
rows_equal(flipped, matrix[j], matrixColSize[0]))
same_row_cnt++;
if (same_row_cnt > ans)
ans = same_row_cnt;
}
free(flipped);
return ans;
}
int main() {
int m1i[2][2] = {{0, 1}, {1, 1}}, m2i[2][2] = {{0, 1}, {1, 0}},
m3i[3][3] = {{0, 0, 0}, {0, 0, 1}, {1, 1, 0}};
struct two_d_arr m1, m2, m3;
two_d_arr_init(&m1, 2, 2, m1i);
two_d_arr_init(&m2, 2, 2, m2i);
two_d_arr_init(&m3, 3, 3, m3i);
printf("%d\n", maxEqualRowsAfterFlips(m1.arr, m1.row_size,
m1.col_size)); // expect: 1
printf("%d\n", maxEqualRowsAfterFlips(m2.arr, m2.row_size,
m2.col_size)); // expect: 2
printf("%d\n", maxEqualRowsAfterFlips(m3.arr, m3.row_size,
m3.col_size)); // expect: 2
two_d_arr_free(&m1);
two_d_arr_free(&m2);
two_d_arr_free(&m3);
}
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