// 2373. Largest Local Values in a Matrix #include "leetcode.h" /* * given an 'n * n' integer matrix grid. generate an integer matrix 'max_local' * of size '(n - 2) * (n - 2)' such that 'max_local[i][j]' is equal to the * largest value of the 3 * 3 matrix in 'grid' centred around row 'i + 1' and * column 'j + 1'. in other words, we want to find the largest value in every * contiguous 3 * 3 matrix in 'grid'. return the generated matrix. */ int **largestLocal(int **grid, int gridSize, int *gridColSize, int *returnSize, int **returnColumnSizes) { *returnSize = gridSize - 2; *returnColumnSizes = (int *)malloc((gridSize - 2) * sizeof(int)); for (int i = 0; i < gridSize - 2; ++i) (*returnColumnSizes)[i] = gridSize - 2; int **ans = (int **)malloc((gridSize - 2) * sizeof(int *)); for (int i = 0; i < gridSize - 2; ++i) ans[i] = (int *)malloc((gridSize - 2) * sizeof(int)); for (int i = 0; i < gridSize - 2; ++i) for (int j = 0; j < gridSize - 2; ++j) { for (int row = 0; row <= 2; ++row) { int max = 0; for (int col = 0; col <= 2; ++col) if (grid[i + row][j + col] > max) max = grid[i + row][j + col]; ans[i][j] = max; max = 0; } } return ans; } int main() { int g1[4][4], g2[5][5], gcs1[] = {4, 4, 4, 4}, gcs2[] = {5, 5, 5, 5, 5}, rs1, rs2, *rcs1, *rcs2; g1[0][0] = 9, g1[0][1] = 9, g1[0][2] = 8, g1[0][3] = 1; g1[1][0] = 5, g1[1][1] = 6, g1[1][2] = 2, g1[1][3] = 6; g1[2][0] = 8, g1[2][1] = 2, g1[2][2] = 6, g1[2][3] = 4; g1[3][0] = 6, g1[3][1] = 2, g1[3][2] = 2, g1[3][3] = 2; for (int i = 0; i < 5; i++) for (int j = 0; j < 5; j++) g2[i][j] = 1; int **ll1 = largestLocal((int **)g1, 4, gcs1, &rs1, &rcs1); int **ll2 = largestLocal((int **)g2, 5, gcs2, &rs2, &rcs2); for (int i = 0; i < rs1; i++) for (int j = 0; j < rs1; j++) printf("%d ", ll1[i][j]); printf("\n"); for (int i = 0; i < rs2; i++) for (int j = 0; j < rs2; j++) printf("%d ", ll2[i][j]); printf("\n"); }