364. Nested List Weight Sum II

Description

You are given a nested list of integers nestedList. Each element is either an integer or a list whose elements may also be integers or other lists.

The depth of an integer is the number of lists that it is inside of. For example, the nested list [1,[2,2],[[3],2],1] has each integer's value set to its depth. Let maxDepth be the maximum depth of any integer.

The weight of an integer is maxDepth - (the depth of the integer) + 1.

Return the sum of each integer in nestedList multiplied by its weight.

Example 1:

Input: nestedList = [[1,1],2,[1,1]]
Output: 8
Explanation: Four 1's with a weight of 1, one 2 with a weight of 2.
1*1 + 1*1 + 2*2 + 1*1 + 1*1 = 8

Example 2:

Input: nestedList = [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

Constraints:

1 <= nestedList.length <= 50
The values of the integers in the nested list is in the range [-100, 100].
The maximum depth of any integer is less than or equal to 50.

Solutions

Solution 1

Python Code

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# """
# This is the interface that allows for creating nested lists.
# You should not implement it, or speculate about its implementation
# """
# class NestedInteger:
#    def __init__(self, value=None):
#        """
#        If value is not specified, initializes an empty list.
#        Otherwise initializes a single integer equal to value.
#        """
#
#    def isInteger(self):
#        """
#        @return True if this NestedInteger holds a single integer, rather than a nested list.
#        :rtype bool
#        """
#
#    def add(self, elem):
#        """
#        Set this NestedInteger to hold a nested list and adds a nested integer elem to it.
#        :rtype void
#        """
#
#    def setInteger(self, value):
#        """
#        Set this NestedInteger to hold a single integer equal to value.
#        :rtype void
#        """
#
#    def getInteger(self):
#        """
#        @return the single integer that this NestedInteger holds, if it holds a single integer
#        Return None if this NestedInteger holds a nested list
#        :rtype int
#        """
#
#    def getList(self):
#        """
#        @return the nested list that this NestedInteger holds, if it holds a nested list
#        Return None if this NestedInteger holds a single integer
#        :rtype List[NestedInteger]
#        """
class Solution:
    def depthSumInverse(self, nestedList: List[NestedInteger]) -> int:
        def max_depth(nestedList):
            depth = 1
            for item in nestedList:
                if item.isInteger():
                    continue
                depth = max(depth, max_depth(item.getList()) + 1)
            return depth

        def dfs(nestedList, max_depth):
            depth_sum = 0
            for item in nestedList:
                if item.isInteger():
                    depth_sum += item.getInteger() * max_depth
                else:
                    depth_sum += dfs(item.getList(), max_depth - 1)
            return depth_sum

        depth = max_depth(nestedList)
        return dfs(nestedList, depth)

Java Code

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/**
 * // This is the interface that allows for creating nested lists.
 * // You should not implement it, or speculate about its implementation
 * public interface NestedInteger {
 *     // Constructor initializes an empty nested list.
 *     public NestedInteger();
 *
 *     // Constructor initializes a single integer.
 *     public NestedInteger(int value);
 *
 *     // @return true if this NestedInteger holds a single integer, rather than a nested list.
 *     public boolean isInteger();
 *
 *     // @return the single integer that this NestedInteger holds, if it holds a single integer
 *     // Return null if this NestedInteger holds a nested list
 *     public Integer getInteger();
 *
 *     // Set this NestedInteger to hold a single integer.
 *     public void setInteger(int value);
 *
 *     // Set this NestedInteger to hold a nested list and adds a nested integer to it.
 *     public void add(NestedInteger ni);
 *
 *     // @return the nested list that this NestedInteger holds, if it holds a nested list
 *     // Return empty list if this NestedInteger holds a single integer
 *     public List<NestedInteger> getList();
 * }
 */
class Solution {
    public int depthSumInverse(List<NestedInteger> nestedList) {
        int depth = maxDepth(nestedList);
        return dfs(nestedList, depth);
    }

    private int maxDepth(List<NestedInteger> nestedList) {
        int depth = 1;
        for (NestedInteger item : nestedList) {
            if (item.isInteger()) {
                continue;
            }
            depth = Math.max(depth, 1 + maxDepth(item.getList()));
        }
        return depth;
    }

    private int dfs(List<NestedInteger> nestedList, int depth) {
        int depthSum = 0;
        for (NestedInteger item : nestedList) {
            if (item.isInteger()) {
                depthSum += item.getInteger() * depth;
            } else {
                depthSum += dfs(item.getList(), depth - 1);
            }
        }
        return depthSum;
    }
}

JavaScript Code

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/**
 * // This is the interface that allows for creating nested lists.
 * // You should not implement it, or speculate about its implementation
 * function NestedInteger() {
 *
 *     Return true if this NestedInteger holds a single integer, rather than a nested list.
 *     @return {boolean}
 *     this.isInteger = function() {
 *         ...
 *     };
 *
 *     Return the single integer that this NestedInteger holds, if it holds a single integer
 *     Return null if this NestedInteger holds a nested list
 *     @return {integer}
 *     this.getInteger = function() {
 *         ...
 *     };
 *
 *     Set this NestedInteger to hold a single integer equal to value.
 *     @return {void}
 *     this.setInteger = function(value) {
 *         ...
 *     };
 *
 *     Set this NestedInteger to hold a nested list and adds a nested integer elem to it.
 *     @return {void}
 *     this.add = function(elem) {
 *         ...
 *     };
 *
 *     Return the nested list that this NestedInteger holds, if it holds a nested list
 *     Return null if this NestedInteger holds a single integer
 *     @return {NestedInteger[]}
 *     this.getList = function() {
 *         ...
 *     };
 * };
 */
/**
 * @param {NestedInteger[]} nestedList
 * @return {number}
 */
var depthSumInverse = function (nestedList) {
    const maxDepth = nestedList => {
        let depth = 1;
        for (const item of nestedList) {
            if (item.isInteger()) {
                continue;
            }
            depth = Math.max(depth, 1 + maxDepth(item.getList()));
        }
        return depth;
    };
    const dfs = (nestedList, depth) => {
        let depthSum = 0;
        for (const item of nestedList) {
            if (item.isInteger()) {
                depthSum += item.getInteger() * depth;
            } else {
                depthSum += dfs(item.getList(), depth - 1);
            }
        }
        return depthSum;
    };
    const depth = maxDepth(nestedList);
    return dfs(nestedList, depth);
};

364. Nested List Weight Sum II#

Description#

Solutions#

Solution 1#

364. Nested List Weight Sum II

Description

Solutions

Solution 1