遞歸實現
static public bool IsSameTree(TreeNode root1, TreeNode root2) { if (root1 == null && root2 == null) { return true; } if ((root1 == null && root2 != null) || (root1 != null && root2 == null)) { return false; } if (root1.val != root2.val) {//判斷每個節點的值是否相等，如果去除此判斷，則判斷兩個二叉樹是否結構相等 return false; } return IsSameTree(root1.left, root2.left) && IsSameTree(root1.right, root2.right);}
非遞歸實現方式
bool BTreeCompare（BTreeNode_t *pRoot1, BTreeNode_t *pRoot2) { if( pRoot1 == NULL && pRoot2 == NULL ) return false; queue <BTreeNode_t *> que1; queue <BTreeNode_t *> que2; que1.push(pRoot1); que2.push(pRoot2); int curLevelNodeTotal1 = 0; int curLevelNodeTotal2 = 0; bool flag = true; //作為比較不一致時跳出標識 while( ( !que1.empty()) && ( !que2.empty())) //當兩個隊列均不為空時，才進行比較 { curLevelNodeTotal1 = que1.size(); //獲取樹1的當前層節點總數 curLevelNodeTotal2 = que2.size(); //獲取樹2的當前層節點總數 if( curLevelNodeTotal1 != curLevelNodeTotal2){ flag = false;//當前層節點總數都不一致，不需要比較了，直接跳出 break; } int cnt1 = 0;//遍歷本層節點時的計數器 int cnt2 = 0; while( cnt1 < curLevelNodeTotal1 && cnt2 < curLevelNodeTotal2){ ++cnt1; ++cnt2; pRoot1 = que1.front(); que1.pop(); pRoot2 = que2.front(); que2.pop(); //比較當前節點中數據是否一致 if( pRoot1->m_pElemt != pRoot2->m_pElemt ){ flag = false; break; } //判斷pRoot1和pRoot2左右節點結構是否相同 if( ( pRoot1->m_pLeft != NULL && pRoot2->m_pLeft == NULL ) || ( pRoot1->m_pLeft == NULL && pRoot2->m_pLeft != NULL ) || ( pRoot1->m_pRight != NULL && pRoot2->m_pRight == NULL ) || ( pRoot1->m_pRight == NULL && pRoot2->m_pRight != NULL ) ){ flag = false; break; } //將左右節點入隊 if( pRoot1->m_pLeft != NULL ) que1.push( pRoot1->m_pLeft); if( pRoot1->m_pRight != NULL ) que1.push( pRoot1->m_pRight); if( pRoot2->m_pLeft != NULL ) que2.push( pRoot2->m_pLeft); if( pRoot2->m_pRight != NULL ) que2.push( pRoot2->m_pRight); } if( flag == false ) break; } //如果比較標志為false，則不相同 if( flag == false ){ while( !que1.empty() ) que1.pop(); while( !que2.empty()) que2.pop(); return false; } return true; }