// 3446. Sort Matrix by Diagonals #include "leetcode.h" /* * you are given an 'n x n' square matrix of integers 'grid'. return the matrix * such that the diagonals in the bottom left triangle including the middle are * sorted in non-increasing order. the diagonals in the top-right triangle are * sorted in non-decreasing order. */ int cmp1(const void *a, const void *b) { return (*(int *)a - *(int *)b); } int cmp2(const void *a, const void *b) { return (*(int *)b - *(int *)a); } int **sortMatrix(int **grid, int gridSize, int *gridColSize, int *returnSize, int **returnColumnSizes) { *returnSize = gridSize; *returnColumnSizes = gridColSize; int n = gridSize, m = gridColSize[0]; int diag_cnt = n + m - 1; int *sizes = (int *)calloc(diag_cnt, sizeof(int)); int **diags = (int **)malloc(diag_cnt * sizeof(int *)); for (int i = 0; i < n; i++) for (int j = 0; j < m; j++) sizes[i - j + m - 1]++; for (int k = 0; k < diag_cnt; k++) { diags[k] = (int *)malloc(sizes[k] * sizeof(int)); sizes[k] = 0; } for (int i = 0; i < n; i++) for (int j = 0; j < m; j++) diags[i - j + m - 1][sizes[i - j + m - 1]++] = grid[i][j]; for (int k = 0; k < diag_cnt; k++) { if (k < m - 1) qsort(diags[k], sizes[k], sizeof(int), cmp1); else qsort(diags[k], sizes[k], sizeof(int), cmp2); sizes[k] = 0; } for (int i = 0; i < n; i++) for (int j = 0; j < m; j++) grid[i][j] = diags[i - j + m - 1][sizes[i - j + m - 1]++]; for (int i = 0; i < diag_cnt; i++) free(diags[i]); free(diags); free(sizes); return grid; } int main() { int g1i[3][3] = {{1, 7, 3}, {9, 8, 2}, {4, 5, 6}}, rs1, *rcs1; int g2i[2][2] = {{0, 1}, {1, 2}}, rs2, *rcs2; int g3i[1][1] = {{1}}, rs3, *rcs3; struct two_d_arr *g1 = two_d_arr_init(ARRAY_SIZE(g1i), ARRAY_SIZE(g1i[0]), g1i); struct two_d_arr *g2 = two_d_arr_init(ARRAY_SIZE(g2i), ARRAY_SIZE(g2i[0]), g2i); struct two_d_arr *g3 = two_d_arr_init(ARRAY_SIZE(g3i), ARRAY_SIZE(g3i[0]), g3i); int **sm1 = sortMatrix(g1->arr, g1->row_size, g1->col_size, &rs1, &rcs1); int **sm2 = sortMatrix(g2->arr, g2->row_size, g2->col_size, &rs2, &rcs2); int **sm3 = sortMatrix(g3->arr, g3->row_size, g3->col_size, &rs3, &rcs3); for (int i = 0; i < rs1; i++) { for (int j = 0; j < rcs1[i]; j++) printf("%d ", sm1[i][j]); // expect: [[8,2,3],[9,6,7],[4,5,1]] printf("\n"); } for (int i = 0; i < rs2; i++) { for (int j = 0; j < rcs2[i]; j++) printf("%d ", sm2[i][j]); // expect: [[2,1],[1,0]] printf("\n"); } for (int i = 0; i < rs3; i++) { for (int j = 0; j < rcs3[i]; j++) printf("%d ", sm3[i][j]); // expect: [[1]] printf("\n"); } for (int i = 0; i < rs1; i++) free(sm1[i]); free(sm1); for (int i = 0; i < rs2; i++) free(sm2[i]); free(sm2); for (int i = 0; i < rs3; i++) free(sm3[i]); free(sm3); free(rcs1); free(rcs2); free(rcs3); two_d_arr_free(g1); two_d_arr_free(g2); two_d_arr_free(g3); }