solve.cpp

#include <queue>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
struct TreeNode {
    int val;
    TreeNode *left;
    TreeNode *right;
    TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
};
typedef struct bucket{
	TreeNode *node;
	int level;
	bucket(TreeNode *n, int l):node(n), level(l){}
} bucket, *Bucket;
class Solution {
public:
    vector<int> rightSideView(TreeNode *root) {
	    vector<int> result;
	    if (root == nullptr)
		    return result;
	    queue<bucket> q;
	    q.push(bucket(root, 0));
	    int level = 0;
	    while (!q.empty()) {
		    auto b = q.front();
		    q.pop();
		    auto p = b.node;
		    if (p->left)
			    q.push(bucket(p->left, level + 1));
		    if (p->right)
			    q.push(bucket(p->right, level + 1));
		    if (q.empty() || q.front().level != level) {
			    result.push_back(p->val);
			    level = q.front().level;
		    }
	    }
	    return result;
    }
};
void mk_children(TreeNode *root, int left, int right)
{
	root->left = new TreeNode(left);
	root->right = new TreeNode(right);
}
void mk_children(TreeNode *root, TreeNode *left, TreeNode *right)
{
	root->left = left;
	root->right = right;
}
int main(int argc, char **argv)
{
	Solution solution;
	TreeNode *root = new TreeNode(1);
	mk_children(root, 2, 3);
	mk_children(root->left, nullptr, new TreeNode(5));
	//mk_children(root->right, new TreeNode(4), nullptr);
	auto result = solution.rightSideView(root);
	for_each(result.begin(), result.end(), [](int i){cout << i << ' ';});
	cout << endl;
	return 0;
}