解题图解： 

 下面是代码：

/*** Note: The returned array must be malloced, assume caller calls free().*/
int* addToArrayForm(int* num, int numSize, int k, int* returnSize){int k_tem =k;int klen=0;while(k_tem){//看看k有几位k_tem /=10;klen++;}int len = numSize>klen?numSize:klen;int *arry =(int*)malloc(sizeof(int)*(len+1));int num_end=numSize-1;int number_in=0;for(int i=0;i<len;i++){int a=0;if(num_end>=0){//k的位数比提供的数组大的情况a=num[num_end];}int bit_number=a+k%10+number_in;k/=10;number_in=0;if(bit_number>=10){arry[i]=bit_number-10;number_in=1;}else{arry[i]=bit_number;}num_end--;}int flag=0;//用于判断开辟的数组最后是len，还是len+1if(number_in==1){//如果最后一位需要进位就让开辟好的数组最后一位置为1arry[len]=1;flag=1;}int arry_end=(flag==1?len:len-1);int arry_start=0;while(arry_start<arry_end){//不用临时变量交换数组，可以学一下arry[arry_start]=arry[arry_start]^arry[arry_end];arry[arry_end]=arry[arry_start]^arry[arry_end];arry[arry_start]=arry[arry_start]^arry[arry_end];arry_end--;arry_start++;}*returnSize=(flag==1?len+1:len);return arry;
}