Verify Max Heap - Amazon Top Interview Questions
Problem Statement :
Given a list of integers nums, return whether it represents a max heap. That is, for every i we have that: nums[i] ≥ nums[2*i + 1] if 2*i + 1 is within bounds nums[i] ≥ nums[2*i + 2] if 2*i + 2 is within bounds Constraints 0 ≤ n ≤ 100,000 where n is the length of nums Example 1 Input nums = [4, 2, 3, 0, 1] Output True
Solution :
Solution in C++ :
bool check(vector<int>& A, int i) {
return (i >= A.size())
? true
: ((A[i] >= ((i * 2 + 1 < A.size()) ? A[i * 2 + 1] : INT_MIN)) &
(A[i] >= ((i * 2 + 2 < A.size()) ? A[i * 2 + 2] : INT_MIN)) & check(A, i + 1));
}
bool solve(vector<int>& nums) {
return check(nums, 0);
}
Solution in Java :
import java.util.*;
class Solution {
public boolean solve(int[] nums) {
for (int i = 0; i < nums.length; i++) {
int k = 2 * i + 1;
boolean result = true;
if (k < nums.length)
result = result && nums[i] >= nums[k];
if (k + 1 < nums.length)
result = result && nums[i] >= nums[k + 1];
if (!result)
return result;
}
return true;
}
}
Solution in Python :
class Solution:
def solve(self, nums):
for i in range(len(nums)):
j = 2 * i + 1
if j < len(nums) and nums[i] < nums[j]:
return False
if j + 1 < len(nums) and nums[i] < nums[j + 1]:
return False
return True
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