[1019] Next Greater Node In Linked List

的確是用了stack ! 的確是要存index 再去寫到return array !

不過雙重轉換的部分果然是搞砸了  XD

然後 if else 的部分，倒過來寫就顯得行數比較少這樣XD

但是好好的拆開的寫法 仍舊比較符合我的思考邏輯 QQ

留在code 裡面。以上!

/**

* Definition for singly-linked list.

* struct ListNode {

* int val;

* struct ListNode *next;

* };

*/

/**

* Note: The returned array must be malloced, assume caller calls free().

*/

int* nextLargerNodes(struct ListNode* head, int* returnSize) {

int *nodes = calloc (10000, sizeof(int));

int count = 0;

struct ListNode* ptr = head;

while (ptr != NULL)

{

nodes[count++]= ptr->val;

ptr = ptr->next;

}

int *stack = calloc (count, sizeof(int));

int *ret = calloc (count, sizeof(int));

int idx = -1;

//do the stack thing

for (int i=0; i<count; i++)

{

#if 1

while (idx >=0 && nodes[i]> nodes[stack[idx]])

ret[stack[idx--]] = nodes[i];

stack[++idx] = i;

#else

if (idx<0 || nodes[i] <= nodes[stack[idx]] ) //push

stack[++idx] = i;

else // pop & push

{

while (idx >=0 && nodes[i]> nodes[stack[idx]])

ret[stack[idx--]] = nodes[i];

stack[++idx] = i;

}

#endif

}

*returnSize = count;

return ret;

}