对称的二叉树
class Solution {
public:bool Compare(TreeNode* left,TreeNode* right){if(left == NULL && right == NULL)return true;if(left == NULL || right == NULL)return false;return left->val == right->val && Compare(left->left,right->right)&& Compare(left->right,right->left);}bool isSymmetrical(TreeNode* pRoot){if(pRoot == NULL)return true;return Compare(pRoot->left,pRoot->right);}};
顺时针打印矩阵
void print_circle(vector< vector<int> > &arr,int a,int b,int c,int d)
{if (a == c){for(int i=b;i<=d;i++)cout<<arr[a][i]<<" ";}else if(b == d){for(int i=a;i<=c;i++)cout<<arr[i][b]<<" ";}else{int row = a;int column = b;while(column != d)cout<<arr[a][column++]<<" ";while(row != c)cout<<arr[row++][column]<<" ";while(column != b)cout<<arr[c][column--]<<" ";while(row != a)cout<<arr[row--][b]<<" ";}
}