Class Solution
Medium
You are given an integer n
representing the number of nodes in a perfect binary tree consisting of nodes numbered from 1
to n
. The root of the tree is node 1
and each node i
in the tree has two children where the left child is the node 2 * i
and the right child is 2 * i + 1
.
Each node in the tree also has a cost represented by a given 0-indexed integer array cost
of size n
where cost[i]
is the cost of node i + 1
. You are allowed to increment the cost of any node by 1
any number of times.
Return the minimum number of increments you need to make the cost of paths from the root to each leaf node equal.
Note:
- A perfect binary tree is a tree where each node, except the leaf nodes, has exactly 2 children.
- The cost of a path is the sum of costs of nodes in the path.
Example 1:
Input: n = 7, cost = [1,5,2,2,3,3,1]
Output: 6
Explanation: We can do the following increments:
- Increase the cost of node 4 one time.
- Increase the cost of node 3 three times.
- Increase the cost of node 7 two times.
Each path from the root to a leaf will have a total cost of 9.
The total increments we did is 1 + 3 + 2 = 6. It can be shown that this is the minimum answer we can achieve.
Example 2:
Input: n = 3, cost = [5,3,3]
Output: 0
Explanation: The two paths already have equal total costs, so no increments are needed.
Constraints:
3 <= n <= 105
n + 1
is a power of2
cost.length == n
1 <= cost[i] <= 104
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Constructor Summary
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Method Summary
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
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Constructor Details
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Solution
public Solution()
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Method Details
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minIncrements
public int minIncrements(int n, int[] cost)
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