王道P205

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

vector<int> a;

typedef struct Node{
    int data;
    struct Node *l, *r;
}BNode, *BTree;

void inorder(BTree p, int sum, vector<int> &a){
    if(!p)  return;
    int x = p -> data;
    a.push_back(x);
    if(! p -> l && ! p -> r){
        if(sum + x == 22){
            for(int i = 0; i < a.size(); i ++)  printf("%d ", a[i]);
            puts("");
        }
    }
    inorder(p -> l, sum + x, a);
    inorder(p -> r, sum + x, a);
    a.pop_back();
}

int main(){

    BNode *p = new BNode[20];
    p -> data = 10, p -> l = (p + 1), p -> r = (p + 2);
    (p + 1) -> data = 5, (p + 1) -> l = (p + 3), (p + 1) -> r = (p + 4);
    (p + 2) -> data = 12, (p + 2) -> l = NULL, (p + 2) -> r = NULL;
    (p + 3) -> data = 4, (p + 3) -> l = NULL, (p + 3) -> r = NULL;
    (p + 4) -> data = 7, (p + 4) -> l = NULL, (p + 4) -> r = NULL;

    inorder(p, 0, a);

    return 0;
}