Merge pull request #2780 from mdmzfzl/main

Create: 0090-subsets-ii.c

Author: mdmzfzl

Diff for: c/0090-subsets-ii.c

@@ -0,0 +1,40 @@
+void backtrack(int* nums, int numsSize, int start, int* subset, int subsetSize, int*** result, int* resultSize, int** resultColSizes) {
+    // Add the current subset to the result set
+    *result = (int**)realloc(*result, (*resultSize + 1) * sizeof(int*));
+    (*result)[*resultSize] = (int*)malloc(subsetSize * sizeof(int));
+    for (int i = 0; i < subsetSize; i++) {
+        (*result)[*resultSize][i] = subset[i];
+    }
+    (*resultColSizes) = (int*)realloc(*resultColSizes, (*resultSize + 1) * sizeof(int));
+    (*resultColSizes)[*resultSize] = subsetSize;
+    (*resultSize)++;
+
+    // Backtracking
+    for (int i = start; i < numsSize; i++) {
+        // Skip duplicates to avoid duplicates in subsets
+        if (i > start && nums[i] == nums[i - 1]) {
+            continue;
+        }
+
+        subset[subsetSize] = nums[i];
+        backtrack(nums, numsSize, i + 1, subset, subsetSize + 1, result, resultSize, resultColSizes);
+    }
+}
+
+int compare(const void* a, const void* b) {
+    return *(int*)a - *(int*)b;
+}
+
+int** subsetsWithDup(int* nums, int numsSize, int* returnSize, int** returnColumnSizes) {
+    qsort(nums, numsSize, sizeof(int), compare);
+    int** result = NULL;
+    int* resultColSizes = NULL;
+    int* subset = (int*)malloc(numsSize * sizeof(int));
+    *returnSize = 0;
+
+    backtrack(nums, numsSize, 0, subset, 0, &result, returnSize, &resultColSizes);
+
+    *returnColumnSizes = resultColSizes;
+    free(subset);
+    return result;
+}