https://leetcode.cn/problems/random-pick-index/

---

根据题目所知，所给的数组中有重复的元素。让我们随机输出给定的目标数字的下标索引。

typedef struct {
    int *sum;
    int length;
} Solution;

Solution* solutionCreate(int* nums, int numsSize) {
    Solution* obj = (Solution*)malloc(sizeof(Solution));
    obj->sum = nums;
    obj->length = numsSize;
    return obj;
}

int solutionPick(Solution* obj, int target) {
    int count = 0;
    int *num = (int*)malloc(sizeof(int)*obj->length);
    
    for(int i = 0; i< obj->length ; i++)
    {
        if(target == obj->sum[i])
        {
            num[count++] = i;
        }
    }

    int ret = num[rand() % count];
    free(num);
    return ret;
}

void solutionFree(Solution* obj) {
    free(obj);
}