二叉树根到叶节点求和值匹配

    题目大意：一颗二叉树，每个节点都有一个Value, 判断根节点到叶节点的路径求和值是否等于某个数Sum.

比如说如下这样一颗二叉树，76是45，21,10这条路径的求和值，77就没有满足条件的路径。

                            45

                    21            65

               10    24      50   70

代码依旧用C++来实现，二叉树一般采用递归的方式来解决。

 

 1 #include <iostream>

 2 

 3 using namespace std;

 4 

 5 typedef struct BTree

 6 

 7 {

 8         int value;

 9         struct BTree* left;

10         struct BTree* right;

11 } BTree;

12 typedef struct BTree Node;

13 

14 //recursively insert a tree node   

15 

16 BTree* Insert(BTree* T, int value)

17 {

18       if(T == NULL)

19       {

20         T = (BTree*)malloc(sizeof(struct BTree));

21         if(T == NULL)

22                 printf("Malloc failed");

23         else{

24                 T->value = value;

25                 T->left = T->right = NULL;

26         }

27       }

28       else if(value < T->value)

29         T->left = Insert(T->left,value);

30       else if(value > T->value)

31         T->right = Insert(T->right,value);

32       return T;

33 }

34 BTree* MakeEmpty(BTree* T)

35 {

36         if(T != NULL){

37                 MakeEmpty(T->left);

38                 MakeEmpty(T->right);

39                 free(T);

40         }

41         return NULL;

42 }

43 

44 

45 bool hasPathSum( Node *node, int sum, int pathSum)

46 {

47         bool match = false;

48         if(node != NULL)

49                 pathSum += node->value;

50         if(node->left== NULL && node->right == NULL)

51         {

52                 if(sum == pathSum)

53                         match = true;

54                 else

55                         match = false;

56         }

57         if(node->left != NULL && !match)

58                 match = hasPathSum(node->left,sum,pathSum);

59         if(node->right != NULL && !match)

60                 match = hasPathSum(node->right,sum,pathSum);

61         return match;

62 }

63 bool hasPathSum( Node *root, int sum)

64 {

65         if(root == NULL) return false;

66          bool match = false;

67          match = hasPathSum(root,sum,0);

68          return match;

69 }

70 int main()

71 {

72         BTree* T = NULL;

73         T = Insert(T,45);

74         T = Insert(T,21);

75         T = Insert(T,65);

76         T = Insert(T,10);

77         T = Insert(T,50);

78         T = Insert(T,70);

79         T = Insert(T,24);

80         bool match = hasPathSum(T,76);

81         cout << match << endl;

82         match = hasPathSum(T,77);

83         cout << match << endl;

84         MakeEmpty(T);

85         return 0;

86 }

View Code