Please suggest an approach to solve this problem. (Problem Link)
# | User | Rating |
---|---|---|
1 | tourist | 3880 |
2 | jiangly | 3669 |
3 | ecnerwala | 3654 |
4 | Benq | 3627 |
5 | orzdevinwang | 3612 |
6 | Geothermal | 3569 |
6 | cnnfls_csy | 3569 |
8 | jqdai0815 | 3532 |
9 | Radewoosh | 3522 |
10 | gyh20 | 3447 |
# | User | Contrib. |
---|---|---|
1 | awoo | 161 |
2 | maomao90 | 160 |
3 | adamant | 156 |
4 | maroonrk | 153 |
5 | atcoder_official | 149 |
6 | -is-this-fft- | 148 |
6 | SecondThread | 148 |
8 | Petr | 147 |
9 | Vladosiya | 144 |
9 | nor | 144 |
Please suggest an approach to solve this problem. (Problem Link)
Name |
---|
Firstly we have to convert the tree queries into array queries. We can perform a dfs and using start and end times , convert the tree to an array. Then each subtree is a range l to r in the array. Now according to the question we have to count the nodes in the subtree rooted at X with value between l to r. That is a range query in array which can be handled using segment tree.
According to me, it was required to run BFS/DFS from node x and check the heights of all nodes in subtree to be in range [L,R]. I constructed a directed graph and followed this approach which gave me WA. Can you tell why this approach is wrong?