Cây nhị phân là cấu trúc dữ liệu dạng cây trong đó mỗi nút có nhiều nhất hai nút con, được định nghĩa là nút con bên trái và nút con bên phải.
Thuật toán
Begin function identical(): Take two nodes r1 and r2 as parameter. If r1 and r2 is NULL then Return true. If r1 or r2 is NULL then Return false. Return (r1->d is equal to r2->d and Call function Identical(r1->l, r2->l) and Call functions Identical(r1->r, r2->r) ); function Subtree(node *T, node *S) : if (S == NULL) then return true; if (T == NULL) then return false; if (call function Identical(T, S)) return true; return Subtree(T->l, S) or Subtree(T->r, S); End.
Mã mẫu
#include <iostream>
using namespace std;
struct n {
int d;
struct n* l;
struct n* r;
};
bool Identical(struct n * r1, struct n *r2) {
if (r1 == NULL && r2 == NULL)
return true;
if (r1 == NULL || r2 == NULL)
return false;
return (r1->d == r2->d && Identical(r1->l, r2->l) && Identical(r1->r, r2->r) );
}
bool Subtree(struct n *T, struct n *S) {
if (S == NULL)
return true;
if (T == NULL)
return false;
if (Identical(T, S))
return true;
return Subtree(T->l, S) || Subtree(T->r, S);
}
struct n* newN(int d) {
struct n* nod =
(struct n*)malloc(sizeof(struct n));
nod->d = d;
nod->l = NULL;
nod->r = NULL;
return(nod);
}
int main() {
struct n *T = newN(24);
T->r = newN(2);
T->r->r = newN(5);
T->l = newN(7);
T->l->l = newN(3);
T->l->l->r = newN(40);
T->l->r = newN(6);
struct n *S = newN(20);
S->r = newN(5);
S->l = newN(3);
S->l->r = newN(50);
if (Subtree(T, S))
cout<<"given tree is subtree of Binary tree"<<"\n";
else
cout<<"given tree is not subtree of Binary tree"<<"\n";
struct n *T1 = newN(30);
T1->r = newN(20);
T1->r->r = newN(19);
T1->l = newN(17);
T1->l->l = newN(4);
T1->l->l->r = newN(40);
T1->l->r = newN(15);
struct n *S1 = newN(17);
S1->r = newN(15);
S1->l = newN(4);
S1->l->r = newN(40);
if (Subtree(T1, S1))
cout<<"given tree is subtree of Binary tree";
else
cout<<"given tree is not subtree of Binary tree";
getchar();
return 0;
} Đầu ra
given tree is not subtree of Binary tree given tree is subtree of Binary tree