Leetcode - Nested List Weight Sum II
https://leetcode.com/problems/nested-list-weight-sum-ii/
Given a nested list of integers, return the sum of all integers in the list weighted by their depth.
Each element is either an integer, or a list -- whose elements may also be integers or other lists.
Different from the previous question where weight is increasing from root to leaf, now the weight is defined from bottom up. i.e., the leaf level integers have weight 1, and the root level integers have the largest weight.
Example 1:
Input: [[1,1],2,[1,1]] Output: 8 Explanation: Four 1's at depth 1, one 2 at depth 2.
Example 2:
Input: [1,[4,[6]]] Output: 17 Explanation: One 1 at depth 3, one 4 at depth 2, and one 6 at depth 1; 1*3 + 4*2 + 6*1 = 17.
/**
* // This is the interface that allows for creating nested lists.
* // You should not implement it, or speculate about its implementation
* type NestedInteger struct {
* }
*
* // Return true if this NestedInteger holds a single integer, rather than a nested list.
* func (n NestedInteger) IsInteger() bool {}
*
* // Return the single integer that this NestedInteger holds, if it holds a single integer
* // The result is undefined if this NestedInteger holds a nested list
* // So before calling this method, you should have a check
* func (n NestedInteger) GetInteger() int {}
*
* // Set this NestedInteger to hold a single integer.
* func (n *NestedInteger) SetInteger(value int) {}
*
* // Set this NestedInteger to hold a nested list and adds a nested integer to it.
* func (n *NestedInteger) Add(elem NestedInteger) {}
*
* // Return the nested list that this NestedInteger holds, if it holds a nested list
* // The list length is zero if this NestedInteger holds a single integer
* // You can access NestedInteger's List element directly if you want to modify it
* func (n NestedInteger) GetList() []*NestedInteger {}
*/
func depthSumInverse(list []*NestedInteger) int {
depth := getDepth(list, 1)
return count(list, depth)
}
func count(list []*NestedInteger, depth int) int {
sum := 0
for _, n := range list {
if n.IsInteger() {
sum += n.GetInteger() * depth
} else {
sum += count(n.GetList(), depth-1)
}
}
return sum
}
func getDepth(list []*NestedInteger, depth int) int {
if len(list) == 0 {
return depth
}
maxDepth := depth
for _, n := range list {
if !n.IsInteger() {
maxDepth = max(maxDepth, getDepth(n.GetList(), depth+1))
}
}
return maxDepth
}
func max(a, b int) int {
if a > b {
return a
}
return b
}
评论 (0)
