Simple DFS.
/**
* // 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 null if this NestedInteger holds a single integer
* public List<NestedInteger> getList();
* }
*/
class Solution {
int sum = 0;
public int depthSum (List<NestedInteger> nestedList) {
depthSum (nestedList, 1);
return sum;
}
private void depthSum(List<NestedInteger> nestedList, int level) {
for (NestedInteger nestedInteger : nestedList) {
if (nestedInteger.isInteger()) {
sum += level * nestedInteger.getInteger();
} else {
depthSum(nestedInteger.getList(), level + 1);
}
}
}
}
364. Nested List Weight Sum II
Two Pass DFS.
/**
* // 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 null if this NestedInteger holds a single integer
* public List<NestedInteger> getList();
* }
*/
class Solution {
int maxLevel = 0;
int sum = 0;
public int depthSumInverse(List<NestedInteger> nestedList) {
getMaxDepth(nestedList, 1);
depthSumInverse(nestedList, 1);
return sum;
}
private void getMaxDepth(List<NestedInteger> nestedList, int level) {
for (NestedInteger nestedInteger : nestedList) {
if (nestedInteger.isInteger()) {
maxLevel = Math.max(maxLevel, level);
} else {
getMaxDepth(nestedInteger.getList(), level + 1);
}
}
}
private void depthSumInverse(List<NestedInteger> nestedList, int level) {
for (NestedInteger nestedInteger : nestedList) {
if (nestedInteger.isInteger()) {
sum += nestedInteger.getInteger() * (maxLevel - level + 1);
} else {
depthSumInverse(nestedInteger.getList(), level + 1);
}
}
}
}