题目一：
Given a binary tree containing digits from 0-9 only, each root-to-leaf
path could represent a number.
An example is the root-to-leaf path 1->2->3 which represents the number 123.
Find the total sum of all root-to-leaf numbers.
For example,
1 / 2 3
The root-to-leaf path 1->2 represents the number 12.
The root-to-leaf path 1->3 represents the number 13.
Return the sum = 12 + 13 = 25.
代码：
/**
* Definition for binary tree
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
int sumNumbers(TreeNode *root)
{
if (root==NULL)
{
return 0;
}
int value = 0;
int sum = 0;
preOrder(root,value,sum);
return sum;
}
private:
int preOrder(TreeNode* root,int & value,int& sum)
{
if (root!=NULL)
{
value = value * 10;
value += root->val;
int revalue = IsHaveLWNode(root);
if (revalue==0)
{
sum+=value;
}
preOrder(root->left,value,sum);
preOrder(root->right,value,sum);
value = value / 10;
return 0;
}
return 0;
}
int IsHaveLWNode(TreeNode* node)
{
if (node->left&&node->right)
{
return 1;
}
else if (node->left)
{
return 2;
}
else if (node->right)
{
return 3;
}
else
{
return 0;
}
}
};
题目二：
Given an unsorted array of integers, find the length of the longest consecutive elements sequence.
For example,
Given [100, 4, 200, 1, 3, 2],
The longest consecutive elements sequence is [1, 2, 3, 4]. Return its
length: 4.
Your algorithm should run in O(n) complexity.
代码：
class Solution {
public:
int longestConsecutive(vector<int> &num)
{
if(num.empty())
{
return 0;
}
int size = num.size();
sort(num.begin(),num.end());
int precount = 1;
int curcount = 1;
for(int i = 1;i<size;i++)
{
if(num[i]==num[i-1]+1)
{
curcount++;
}
else if (num[i]!=num[i-1])
{
if (curcount>precount)
{
precount = curcount;
}
curcount = 1;
}
}
if(precount>curcount)
{
curcount = precount;
}
return curcount;
}
};
leetcode题目：Sum Root to Leaf Numbers和Longest Consecutive Sequence