给定一个整数数组，请在删除给定元素后找到k个最大数。如果重复元素，请为包含要删除元素的数组中存在的元素的每个实例删除一个实例。
假设删除n个元素后将剩余至少k个元素。
例子：
输入：array [] = {5，12，33，4，56，12，20}，del [] = {12，56，5}，k = 3
输出：33 20 12
说明：删除后将保留{33，4，12，20}。从中打印出前3个最高的元素。
方法 ：
- 将所有要从数组中删除的数字插入到哈希图中，以便我们可以检查数组元素是否在O(1)时也出现在Delete-array中。
- 遍历数组。检查元素是否存在于哈希图中。
- 如果存在，请从哈希映射中将其删除。
- 否则，将其插入Max堆中。
- 插入所有要删除的元素(不包括要删除的元素)后，从Max堆中弹出k个元素。
C++
#include "iostream"
#include "queue"
#include "unordered_map"
using namespace std;
// Find k maximum element from arr[0..m-1] after deleting
// elements from del[0..n-1]
void findElementsAfterDel(int arr[], int m, int del[],
int n, int k)
{
// Hash Map of the numbers to be deleted
unordered_map mp;
for (int i = 0; i < n; ++i) {
// Increment the count of del[i]
mp[del[i]]++;
}
// Initializing the largestElement
priority_queue heap;
for (int i = 0; i < m; ++i) {
// Search if the element is present
if (mp.find(arr[i]) != mp.end()) {
// Decrement its frequency
mp[arr[i]]--;
// If the frequency becomes 0,
// erase it from the map
if (mp[arr[i]] == 0)
mp.erase(arr[i]);
}
// Else compare it largestElement
else
heap.push(arr[i]);
}
// Print top k elements in the heap
for (int i = 0; i < k; ++i) {
cout << heap.top() << " ";
// Pop the top element
heap.pop();
}
}
int main()
{
int array[] = { 5, 12, 33, 4, 56, 12, 20 };
int m = sizeof(array) / sizeof(array[0]);
int del[] = { 12, 56, 5 };
int n = sizeof(del) / sizeof(del[0]);
int k = 3;
findElementsAfterDel(array, m, del, n, k);
return 0;
} Java
import java.io.*;
import java.util.*;
class GFG
{
// Find k maximum element from arr[0..m-1] after deleting
// elements from del[0..n-1]
static void findElementsAfterDel(int arr[], int m,
int del[], int n, int k)
{
// Hash Map of the numbers to be deleted
Map mp = new HashMap();
for (int i = 0; i < n; ++i)
{
// Increment the count of del[i]
if(mp.containsKey(del[i]))
{
mp.put(del[i], mp.get(del[i]) + 1);
}
else
{
mp.put(del[i], 1);
}
}
// Initializing the largestElement
PriorityQueue heap =
new PriorityQueue(
Collections.reverseOrder());
for (int i = 0; i < m; ++i)
{
// Search if the element is present
if(mp.containsKey(arr[i]))
{
// Decrement its frequency
mp.put(arr[i], mp.get(arr[i]) - 1);
// If the frequency becomes 0,
// erase it from the map
if(mp.get(arr[i]) == 0)
{
mp.remove(arr[i]);
}
}
// Else compare it largestElement
else
{
heap.add(arr[i]);
}
}
// Print top k elements in the heap
for(int i = 0; i < k; ++i)
{
// Pop the top element
System.out.print(heap.poll() + " ");
}
}
// Driver code
public static void main (String[] args)
{
int array[] = { 5, 12, 33, 4, 56, 12, 20 };
int m = array.length;
int del[] = { 12, 56, 5 };
int n = del.length;
int k = 3;
findElementsAfterDel(array, m, del, n, k);
}
}
// This code is contributed by rag2127 Python3
# Python3 program to find the k maximum
# number from the array after n deletions
import math as mt
# Find k maximum element from arr[0..m-1]
# after deleting elements from del[0..n-1]
def findElementsAfterDel(arr, m, dell, n, k):
# Hash Map of the numbers to be deleted
mp = dict()
for i in range(n):
# Increment the count of del[i]
if dell[i] in mp.keys():
mp[dell[i]] += 1
else:
mp[dell[i]] = 1
heap = list()
for i in range(m):
# Search if the element is present
if (arr[i] in mp.keys()):
# Decrement its frequency
mp[arr[i]] -= 1
# If the frequency becomes 0,
# erase it from the map
if (mp[arr[i]] == 0):
mp.pop(arr[i])
# Else push it
else:
heap.append(arr[i])
heap.sort()
heap = heap[::-1]
return heap[:k]
# Driver code
array = [5, 12, 33, 4, 56, 12, 20]
m = len(array)
dell = [12, 4, 56, 5 ]
n = len(dell)
k = 3
print(*findElementsAfterDel(array, m, dell, n, k))
# This code is contributed by
# mohit kumar 29C#
using System;
using System.Collections.Generic;
class GFG
{
// Find k maximum element from arr[0..m-1] after deleting
// elements from del[0..n-1]
static void findElementsAfterDel(int[] arr, int m,
int[] del, int n, int k)
{
// Hash Map of the numbers to be deleted
Dictionary mp = new Dictionary();
for (int i = 0; i < n; ++i)
{
// Increment the count of del[i]
if(mp.ContainsKey(del[i]))
{
mp[del[i]]++;
}
else
{
mp.Add(del[i], 1);
}
}
// Initializing the largestElement
List heap = new List();
for (int i = 0; i < m; ++i)
{
// Search if the element is present
if(mp.ContainsKey(arr[i]))
{
// Decrement its frequency
mp[arr[i]]--;
// If the frequency becomes 0,
// erase it from the map
if(mp[arr[i]] == 0)
{
mp.Remove(arr[i]);
}
}
// Else compare it largestElement
else
{
heap.Add(arr[i]);
}
}
heap.Sort();
heap.Reverse();
// Print top k elements in the heap
for(int i = 0; i < k; ++i)
{
Console.Write(heap[i] + " ");
}
}
// Driver code
static public void Main ()
{
int[] array = { 5, 12, 33, 4, 56, 12, 20 };
int m = array.Length;
int[] del = { 12, 56, 5 };
int n = del.Length;
int k = 3;
findElementsAfterDel(array, m, del, n, k);
}
}
// This code is contributed by avanitrachhadiya2155 输出：
33 20 12如果您希望与行业专家一起参加现场课程，请参阅《 Geeks现场课程》和《 Geeks现场课程美国》。