1043 Is It a Binary Search Tree 25

 

 

#include <cstdio>
#include <vector>
using namespace std;
const int maxn = 10010;
struct node{
    int data;
    node* l;
    node* r;
};
int n,cur=0;
vector<int> ori,pre,mirror;
void insert(node* &root, int data){
    if(root == NULL){
        root = new node;
        root->data = data;
        root->l = NULL;
        root->r = NULL;
        return;
    }
    if(root->data > data) insert(root->l, data);
    else insert(root->r, data);
}
void preOrder(node* root){
    if(root == NULL) return;
    pre.push_back(root->data);
    preOrder(root->l);
    preOrder(root->r);
}
void mirrOrder(node* root){
    if(root == NULL) return;
    mirror.push_back(root->data);
    mirrOrder(root->r);
    mirrOrder(root->l);
}
void posOrder(node* root){
    if(root == NULL) return;
    posOrder(root->l);
    posOrder(root->r);
    printf("%d", root->data);
    if(cur < n-1){
        printf(" ");
        cur++;
    }
}
void mirrPosOrder(node* root){
    if(root == NULL) return;
    mirrPosOrder(root->r);
    mirrPosOrder(root->l);
    printf("%d", root->data);
    if(cur < n-1){
        printf(" ");
        cur++;
    }
}
int main() {
    scanf("%d", &n);
    node* root = NULL;
    int d;
    for(int i = 0; i < n; i++){
        scanf("%d", &d);
        insert(root, d);
        ori.push_back(d);
    }
    preOrder(root);
    mirrOrder(root);
    if(pre == ori){
        printf("YES\n");
        posOrder(root);
        printf("\n");
    }else if(mirror == ori){
        printf("YES\n");
        mirrPosOrder(root);
        printf("\n");
    }else{
        printf("NO\n");
    }
    return 0;
}