题目：

题解：

int** ans;
int ansSize;
int* temp;
int tempSize;void dfs(int cur, int last, int* nums, int numsSize, int** returnColumnSizes) {if (cur == numsSize) {if (tempSize >= 2) {ans[ansSize] = malloc(sizeof(int) * tempSize);memcpy(ans[ansSize], temp, sizeof(int) * tempSize);(*returnColumnSizes)[ansSize++] = tempSize;}return;}if (nums[cur] >= last) {temp[tempSize++] = nums[cur];dfs(cur + 1, nums[cur], nums, numsSize, returnColumnSizes);tempSize--;}if (nums[cur] != last) {dfs(cur + 1, last, nums, numsSize, returnColumnSizes);}
}int** findSubsequences(int* nums, int numsSize, int* returnSize, int** returnColumnSizes) {ans = malloc(sizeof(int*) * 32768);*returnColumnSizes = malloc(sizeof(int*) * 32768);temp = malloc(sizeof(int) * numsSize);ansSize = tempSize = 0;dfs(0, INT_MIN, nums, numsSize, returnColumnSizes);*returnSize = ansSize;return ans;
}