题目：

题解：

int cmp(int* a, int* b) {
    return *a - *b;
}

int* largestDivisibleSubset(int* nums, int numsSize, int* returnSize) {
    int len = numsSize;
    qsort(nums, numsSize, sizeof(int), cmp);

    // 第 1 步：动态规划找出最大子集的个数、最大子集中的最大整数
    int dp[len];
    for (int i = 0; i < len; i++) {
        dp[i] = 1;
    }
    int maxSize = 1;
    int maxVal = dp[0];
    for (int i = 1; i < len; i++) {
        for (int j = 0; j < i; j++) {
            // 题目中说「没有重复元素」很重要
            if (nums[i] % nums[j] == 0) {
                dp[i] = fmax(dp[i], dp[j] + 1);
            }
        }

        if (dp[i] > maxSize) {
            maxSize = dp[i];
            maxVal = nums[i];
        }
    }

    // 第 2 步：倒推获得最大子集
    int* res = malloc(sizeof(int) * len);
    *returnSize = 0;
    if (maxSize == 1) {
        res[(*returnSize)++] = nums[0];
        return res;
    }

    for (int i = len - 1; i >= 0 && maxSize > 0; i--) {
        if (dp[i] == maxSize && maxVal % nums[i] == 0) {
            res[(*returnSize)++] = nums[i];
            maxVal = nums[i];
            maxSize--;
        }
    }
    return res;
}