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Path Sum II

Given a binary tree and a sum, find all root-to-leaf paths where each path‘s sum equals the given sum.

For example:

Given the below binary tree and sum = 22,

5

/ \

4   8

/   / \

11  13  4

/  \    / \

7    2  5   1

return

[

[5,4,11,2],

[5,8,4,5]

]

class Solution {
public:
    vector<vector<int> > pathSum(TreeNode *root, int sum) {
        vector<vector<int> > ans;
		vector<int> temp;
		if (root!=NULL)
			pathSumUtil(root , sum , 0 , ans , temp);
		return ans;
    }
private:

	void pathSumUtil(TreeNode *root, int sum , int cur , vector<vector<int> > &ans , vector<int> &temp)
	{
		temp.push_back(root->val);
		if(root->left==NULL && root->right==NULL)
		{
			if( cur+root->val == sum )
				ans.push_back(temp);
		}
		else
		{
			if(root->left!=NULL)
				pathSumUtil( root->left, sum, cur+root->val, ans , temp );
			if(root->right!=NULL)
				pathSumUtil( root->right, sum, cur+root->val, ans , temp );
		}
	    temp.pop_back();
	}
};