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Diffstat (limited to 'search_2d_matrix.c')
-rw-r--r-- | search_2d_matrix.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/search_2d_matrix.c b/search_2d_matrix.c new file mode 100644 index 0000000..7e8e7fe --- /dev/null +++ b/search_2d_matrix.c @@ -0,0 +1,35 @@ +// 74. Search a 2D Matrix +#include <stdbool.h> +#include <stdio.h> + +/* + * given an 'm x n' integer matrix 'matrxi' with the following two properties: + * - each row is sorted in non-decreasing order. + * - the first integer of each row is greater than the last integer of the + * previous row. given an integer 'target', return true if 'target' is in + * 'matrix', or false otherwise. you must write a solution in 'O(log(m * n))' + * time complexity + */ + +bool searchMatrix(int **matrix, int matrix_size, int *matrix_col_size, + int target) { + int i = 0, j = *matrix_col_size * matrix_size - 1; + while (i <= j) { + int mid = (i + j) / 2; + int row = mid / *matrix_col_size; + int col = mid % *matrix_col_size; + if (matrix[row][col] < target) + i = mid + 1; + else if (matrix[row][col] > target) + j = mid - 1; + else + return true; + } + return false; +} + +int main() { + int matrix[3][4] = {{1, 3, 5, 7}, {10, 11, 16, 20}, {23, 30, 34, 60}}; + printf("%d\n", searchMatrix(matrix, 4, NULL, 3)); // expect: 1 + printf("%d\n", searchMatrix(matrix, 4, NULL, 13)); // expect: 0 +} |