[LeetCode] Populating Next Right Pointers in Each Node II

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Follow up for problem "Populating Next Right Pointers in Each Node".

What if the given tree could be any binary tree? Would your previous solution still work?

Note:

• You may only use constant extra space.

 

For example, Given the following binary tree,

         1       /        2    3     / \        4   5    7

 

After calling your function, the tree should look like:

         1 -> NULL       /        2 -> 3 -> NULL     / \        4-> 5 -> 7 -> NULL

class Solution {public:    void connect(TreeLinkNode *root) {        if(root==NULL)            return;                root->next = NULL;        fun(root);    }private:    TreeLinkNode *FindPleft(TreeLinkNode *&parent){        TreeLinkNode *pleft =NULL;        while(parent!=NULL){            if(parent->left!=NULL){                pleft = parent->left;                break;            }else if(parent->left==NULL && parent->right!=NULL){               pleft = parent->right;               break;            }else{               parent = parent->next;               continue;            }        }//end while        return pleft;    }    void fun(TreeLinkNode *parent){        if(parent==NULL)            return ;        TreeLinkNode *pleft = FindPleft(parent);        TreeLinkNode *pl;        TreeLinkNode *nextLevelParent = pleft;        while(parent!=NULL){          if(pleft==parent->left &&parent->right!=NULL){           pleft->next = parent->right;           pleft = pleft->next;                  }else if((pleft!=NULL && pleft==parent->left && parent->right==NULL)||pleft==parent->right){              parent = parent->next;              if(parent==NULL||FindPleft(parent)==NULL){                  pleft->next = NULL;                  parent = nextLevelParent;                  pl = FindPleft(parent);                  pleft = pl;                  nextLevelParent = pleft;              }else{                  pl = FindPleft(parent);                  pleft->next = pl;                  pleft = pl;              }          }//end if                         }//end while    }};