int cal_sum(TreeNode* root, int &maxSum)
{
if (root == nullptr)
return 0;
int left = cal_sum(root->left, maxSum);
int right = cal_sum(root->right, maxSum);
int sum = left + right + root->val;
if (sum > maxSum)
maxSum = sum;
int thismax = std::max(left,right);
return std::max(thismax + root->val, root->val);
}
int icmp_pack(char type,int seq,int len,short id)
{
icmp_t *icmp = (void *)(send_buf + sizeof(eth_t) + sizeof(ip_t));
icmp->type = type;
icmp->code = 0;
icmp->checksum = 0;
icmp->id = htons(id);
icmp->sequence = htons(seq);
icmp->checksum = cal_sum((void *)icmp,len + sizeof(*icmp));
return ip_pack(len + sizeof(*icmp), 1);
}
// lucky number defines as the sum of each digit square is 1.
// for example
// 100 = 1^2 + 0^2 + 0^2 = 1
//
// if a number encounts a self-loop, then it is not lucky number.
//
int lucky_number(int n)
{
// max possible value is: 9 * (1^2 + 2^2 + ... + 9^9), and must < 81 * 81
char trace[81 * 81] = {0};
do {
int a[10] = {0};
fill_pattern(n, a);
int new_value = cal_sum(a);
if (new_value == 1) return 1;
if (trace[new_value]) return 0;
trace[new_value] = 1;
n = new_value;
} while (1);
}
int ip_pack(u32 length, u8 type)
{
ip_t *ip = (void *)(send_buf + sizeof(eth_t));
ip->ihl = sizeof(ip_t) >> 2;
ip->version = 4;
ip->tos = 0;
ip->tot_len = htons(sizeof(ip_t) + length);
ip->id = 0;
ip->frag_off = 0;
ip->ttl = 255;
ip->protocol = type;
ip->check = 0;
ip->saddr = eip;
ip->daddr = hip;
ip->check = cal_sum((void *)ip, sizeof(ip_t));
return eth_pack(sizeof(ip_t) + length, 0x0800);
}
int ip_pack(unsigned int length, unsigned char type)
{
ip_h *ip = (void *)(send_buf + sizeof(eth_h));
ip->ihl = sizeof(ip_h) >> 2;
ip->version = 4;
ip->tos = 0;
ip->tot_len = htons(sizeof(ip_h) + length);
ip->id = 0;
ip->frag_off = 0;
ip->ttl = 255;
ip->protocol = type;
ip->check = 0;
ip->saddr = htonl(eip);
ip->daddr = htonl(hip);
ip->check = cal_sum((void *)ip, sizeof(ip_h));
return eth_pack(sizeof(ip_h) + length, 0x0800);
}
int WriteCode::FindMaxPathSum(TreeNode* root){
int maxSum = root->val;
cal_sum(root, maxSum);
return maxSum;
}
