228. Summary Ranges
     
     题目分析：输出数组的连续排序的数字，如果有数字断档就再分接上后续的范围。利用两个指针分别指向连续的两个数字判断是否相差+1，再循环。

char ** summaryRanges(int* nums, int numsSize, int* returnSize){
    char **ret = malloc(sizeof(char*)*20); 
    *returnSize = 0;
    if(numsSize == 0){        
        return NULL;
    }
    if(numsSize == 1){
        ret[0]=calloc(10,sizeof(char));
        sprintf(ret[0],"%d",nums[0]);        
        *returnSize = 1;
        return ret;
    }
    int i,init=nums[0],curr=nums[0];
    for(i=0;i<numsSize-1;i++){
        curr=nums[i];
        if(curr+1!=nums[i+1]){
            if(curr != init){
                ret[*returnSize]=calloc(30,sizeof(char));
                sprintf(ret[*returnSize],"%d->%d",init,nums[i]);                
                *returnSize += 1;
            }
            else{
                ret[*returnSize]=calloc(20,sizeof(char));
                sprintf(ret[*returnSize],"%d",nums[i]);                
                *returnSize += 1;
            }
            init=nums[i+1];
        }
    }
    if(nums[numsSize-2]+1 == nums[numsSize-1]){
        ret[*returnSize]=calloc(30,sizeof(char));
        sprintf(ret[*returnSize],"%d->%d",init,nums[i]);                
        *returnSize += 1;
    }
    else{
        ret[*returnSize]=calloc(20,sizeof(char));
        sprintf(ret[*returnSize],"%d",nums[i]);                
        *returnSize += 1;
    }
    return ret;  
}