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-rw-r--r--flip_equivalent_binary_tree.c94
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diff --git a/flip_equivalent_binary_tree.c b/flip_equivalent_binary_tree.c
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+// 951. Flip Equivalent Binary Trees
+#include "leetcode.h"
+
+/*
+ * for a binarytree T, we can define a flip operation as follows: choose any
+ * node, and swap the left and right child subtrees. a binary tree X is flip
+ * equivalent to a binary tree Y if and only if we can make X equal to Y after
+ * some number of flip operations. given the roots of two binary trees 'root1'
+ * and 'root2', return 'true' if the two trees are flip equivalent.
+ */
+
+//__attribute((naked))
+bool flipEquiv(struct TreeNode *root1, struct TreeNode *root2) {
+ /*
+ __asm("push %rbp;"
+ "mov %rsp,%rbp;"
+ "push %rbx;"
+ "push %r8;"
+ "push %r9;"
+ "xor %eax,%eax;"
+ "test %rdi,%rdi;"
+ "jnz l1;"
+ "test %rsi,%rsi;"
+ "jnz l0;"
+ "add $0x1,%eax;"
+ "jmp l0;"
+ "l1:;"
+ "test %rsi,%rsi;"
+ "jz l0;"
+ "mov (%rdi),%ecx;"
+ "cmp %ecx,(%rsi);"
+ "jne l0;"
+ "mov %rdi,%r8;"
+ "mov %rsi,%r9;"
+ "mov 0x8(%r8),%rdi;"
+ "mov 0x8(%r9),%rsi;"
+ "call flipEquiv;"
+ "xchg %eax,%ebx;"
+ "mov 0x10(%r8),%rdi;"
+ "mov 0x10(%r9),%rsi;"
+ "call flipEquiv;"
+ "and %ebx,%eax;"
+ "jnz l0;"
+ "mov 0x8(%r8),%rdi;"
+ "mov 0x10(%r9),%rsi;"
+ "call flipEquiv;"
+ "xchg %eax,%ebx;"
+ "mov 0x10(%r8),%rdi;"
+ "mov 0x8(%r9),%rsi;"
+ "call flipEquiv;"
+ "and %ebx,%eax;"
+ "l0:;"
+ "pop %r9;"
+ "pop %r8;"
+ "pop %rbx;"
+ "mov %rbp,%rsp;"
+ "pop %rbp;"
+ "pop %rcx;"
+ "jmp %rcx;");
+ */
+ if (!root1 || !root2)
+ return root1 == root2;
+ if (root1->val == root2->val) {
+ return (flipEquiv(root1->left, root2->right) &
+ flipEquiv(root1->right, root2->left)) ||
+ (flipEquiv(root1->left, root2->left) &
+ flipEquiv(root1->right, root2->right));
+ }
+ return false;
+}
+
+int main() {
+ struct TreeNode *r1 = treenode_create(1);
+ r1->left = treenode_create(2);
+ r1->right = treenode_create(3);
+ r1->left->left = treenode_create(4);
+ r1->left->right = treenode_create(5);
+ r1->right->left = treenode_create(6);
+ r1->right->right = NULL;
+ r1->left->right->left = treenode_create(7);
+ r1->left->right->right = treenode_create(8);
+ struct TreeNode *r2 = treenode_create(1);
+ r2->left = treenode_create(3);
+ r2->right = treenode_create(2);
+ r2->left->left = NULL;
+ r2->left->right = treenode_create(6);
+ r2->right->left = treenode_create(4);
+ r2->right->right = treenode_create(5);
+ r2->right->right->left = treenode_create(8);
+ r2->right->right->right = treenode_create(7);
+ printf("%d\n", flipEquiv(r1, r2)); // expect: 1
+ treenode_free(r1);
+ treenode_free(r2);
+}