算法题目---二叉树中和为某一值的路径

输入一棵二叉树和一个整数，打印出二叉树中结点值的各为输入整数的所有路径。从树的根结点开始往下一直到叶结点所经过的结点形成一条路径。

struct BinaryTreeNode

{
    int m_nValue;
    BinaryTreeNode *m_pLeft;
    BinaryTreeNode *m_pRight;
};

void FindPath(BinaryTreeNode *pRoot,int expectedSum,vector<int>&path,int &currentSum)
{
    currentSum += pRoot->m_nValue;
    path.push_back(pRoot->m_nValue);

    bool isLeaf = pRoot->m_pLeft == NULL && pRoot->m_pRight == NULL;

    if(currentSum == expectedSum && isLeaf)
    {
        printf("A path is found: ");
        vector<int>::iterator iter = path.begin();
        for(;iter != path.end();++iter )
        printf("%d\t ",*iter);
        
        printf("\n");
    }
    if(pRoot->m_pLeft != NULL)
        FindPath(pRoot->m_pLeft,expectedSum,path,currentSum);
    if(pRoot->m_pRight != NULL)
        FindPath(pRoot->m_pRight,expectedSum,path,currentSum);

    currentSum -= pRoot->m_nValue;
    path.pop_back();
}

void Find(BinaryTreeNode* pRoot,int expectedSum)
{
    if(pRoot == NULL)
        return;
    vector<int> path;
    int cur = 0;
    FindPath(pRoot,expectedSum,path,cur);
}

void Test(char* testName, BinaryTreeNode* pRoot, int expectedSum)
{
    if(testName != NULL)
        printf("%s begins:\n", testName);

    Find(pRoot, expectedSum);

    printf("\n");
}

BinaryTreeNode* CreateBinaryTreeNode(int value)
{
    BinaryTreeNode* pNode = new BinaryTreeNode();
    pNode->m_nValue = value;
    pNode->m_pLeft = NULL;
    pNode->m_pRight = NULL;

    return pNode;
}

void ConnectTreeNodes(BinaryTreeNode* pParent, BinaryTreeNode* pLeft, BinaryTreeNode* pRight)
{
    if(pParent != NULL)
    {
        pParent->m_pLeft = pLeft;
        pParent->m_pRight = pRight;
    }
}

void DestroyTree(BinaryTreeNode* pRoot)
{
    if(pRoot != NULL)
    {
        BinaryTreeNode* pLeft = pRoot->m_pLeft;
        BinaryTreeNode* pRight = pRoot->m_pRight;

        delete pRoot;
        pRoot = NULL;

        DestroyTree(pLeft);
        DestroyTree(pRight);
    }
}

void Test1()
{
    BinaryTreeNode* pNode10 = CreateBinaryTreeNode(10);
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
    BinaryTreeNode* pNode12 = CreateBinaryTreeNode(12);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
    BinaryTreeNode* pNode7 = CreateBinaryTreeNode(7);

    ConnectTreeNodes(pNode10, pNode5, pNode12);
    ConnectTreeNodes(pNode5, pNode4, pNode7);

    printf("Two paths should be found in Test1.\n");
    Test("Test1", pNode10, 22);

    DestroyTree(pNode10);
}

void Test2()
{
    BinaryTreeNode* pNode10 = CreateBinaryTreeNode(10);
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
    BinaryTreeNode* pNode12 = CreateBinaryTreeNode(12);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
    BinaryTreeNode* pNode7 = CreateBinaryTreeNode(7);

    ConnectTreeNodes(pNode10, pNode5, pNode12);
    ConnectTreeNodes(pNode5, pNode4, pNode7);

    printf("No paths should be found in Test2.\n");
    Test("Test2", pNode10, 15);

    DestroyTree(pNode10);
}

void Test3()
{
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
    BinaryTreeNode* pNode3 = CreateBinaryTreeNode(3);
    BinaryTreeNode* pNode2 = CreateBinaryTreeNode(2);
    BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);

    ConnectTreeNodes(pNode5, pNode4, NULL);
    ConnectTreeNodes(pNode4, pNode3, NULL);
    ConnectTreeNodes(pNode3, pNode2, NULL);
    ConnectTreeNodes(pNode2, pNode1, NULL);

    printf("One path should be found in Test3.\n");
    Test("Test3", pNode5, 15);

    DestroyTree(pNode5);
}

void Test4()
{
    BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);
    BinaryTreeNode* pNode2 = CreateBinaryTreeNode(2);
    BinaryTreeNode* pNode3 = CreateBinaryTreeNode(3);
    BinaryTreeNode* pNode4 = CreateBinaryTreeNode(4);
    BinaryTreeNode* pNode5 = CreateBinaryTreeNode(5);

    ConnectTreeNodes(pNode1, NULL, pNode2);
    ConnectTreeNodes(pNode2, NULL, pNode3);
    ConnectTreeNodes(pNode3, NULL, pNode4);
    ConnectTreeNodes(pNode4, NULL, pNode5);

    printf("No paths should be found in Test4.\n");
    Test("Test4", pNode1, 16);

    DestroyTree(pNode1);
}

void Test5()
{
    BinaryTreeNode* pNode1 = CreateBinaryTreeNode(1);

    printf("One path should be found in Test5.\n");
    Test("Test5", pNode1, 1);

    DestroyTree(pNode1);
}

void Test6()
{
    printf("No paths should be found in Test6.\n");
    Test("Test6", NULL, 0);
}

int main()
{
    Test1();
    Test2();
    Test3();
    Test4();
    Test5();
    Test6();

    return 0;
}