Minimize number of boxes by putting small box inside bigger one

25 Apr, 2022
Given an array size[] of box sizes, our task is to find the number of boxes left at the end, after putting the smaller-sized box into a bigger one. Note: Only one small box can fit inside one box.Examples: 
Input: size[] = {1, 2, 3} Output: 1 Explanation: Here, box of size 1 can fit inside box of size 2 and the box of size 2 can fit inside box of size 3. So at last we have only one box of size 3.
Input: size[] = {1, 2, 2, 3, 7, 4, 2, 1} Output: 3 Explanation: Put the box of size 1, 2, 3, 4 and 7 together and for the second box put 1 and 2 together. At last 2 is left which will not fit inside anyone. So we have 3 boxes left. 
Approach: The idea is to follow the steps given below:
Sort the given array size[] in increasing order and check if the current box size is greater than the next box size. If yes then decrease the initial box number.
Otherwise, if the current box size is equal to next box size, then check if the current box can fit inside next to next box size. If yes then move the current box pointing variable, else move next pointing variable further.
Below is the implementation of the above approach: 
C++
Java
Python3
C#
Javascript
// C++ implementation to minimize the// number of the box by putting small// box inside the bigger one #include <bits/stdc++.h>using namespace std; // Function to minimize the countvoid minBox(int arr[], int n){    // Initial number of box    int box = n;     // Sort array of box size    // in increasing order    sort(arr, arr + n);     int curr_box = 0, next_box = 1;    while (curr_box < n && next_box < n) {         // check is current box size        // is smaller than next box size        if (arr[curr_box] < arr[next_box]) {             // Decrement box count            // Increment current box count            // Increment next box count            box--;            curr_box++;            next_box++;        }         // Check if both box        // have same size        else if (arr[curr_box] == arr[next_box])            next_box++;    }     // Print the result    cout << box << endl;} // Driver codeint main(){    int size[] = { 1, 2, 3 };    int n = sizeof(size) / sizeof(size[0]);    minBox(size, n);    return 0;}
// Java implementation to minimize the// number of the box by putting small// box inside the bigger oneimport java.util.Arrays; class GFG{     // Function to minimize the countpublic static void minBox(int arr[], int n){         // Initial number of box    int box = n;     // Sort array of box size    // in increasing order    Arrays.sort(arr);     int curr_box = 0, next_box = 1;    while (curr_box < n && next_box < n)    {                 // Check is current box size        // is smaller than next box size        if (arr[curr_box] < arr[next_box])        {                         // Decrement box count            // Increment current box count            // Increment next box count            box--;            curr_box++;            next_box++;        }         // Check if both box        // have same size        else if (arr[curr_box] ==                 arr[next_box])            next_box++;    }     // Print the result    System.out.println(box);} // Driver codepublic static void main(String args[]){    int []size = { 1, 2, 3 };    int n = size.length;         minBox(size, n);}} // This code is contributed by SoumikMondal
# Python3 implementation to minimize the# number of the box by putting small# box inside the bigger one # Function to minimize the countdef minBox(arr, n):         # Initial number of box    box = n     # Sort array of box size    # in increasing order    arr.sort()     curr_box, next_box = 0, 1    while (curr_box < n and next_box < n):         # Check is current box size        # is smaller than next box size        if (arr[curr_box] < arr[next_box]):             # Decrement box count            # Increment current box count            # Increment next box count            box = box - 1            curr_box = curr_box + 1            next_box = next_box + 1         # Check if both box        # have same size        elif (arr[curr_box] == arr[next_box]):            next_box = next_box + 1     # Print the result    print(box) # Driver codesize = [ 1, 2, 3 ]n = len(size) minBox(size, n) # This code is contributed by divyeshrabadiya07
// C# implementation to minimize the// number of the box by putting small// box inside the bigger oneusing System; class GFG{     // Function to minimize the countpublic static void minBox(int []arr, int n){         // Initial number of box    int box = n;     // Sort array of box size    // in increasing order    Array.Sort(arr);     int curr_box = 0, next_box = 1;    while (curr_box < n && next_box < n)    {                 // Check is current box size        // is smaller than next box size        if (arr[curr_box] < arr[next_box])        {                         // Decrement box count            // Increment current box count            // Increment next box count            box--;            curr_box++;            next_box++;        }         // Check if both box        // have same size        else if (arr[curr_box] ==                 arr[next_box])            next_box++;    }     // Print the result    Console.WriteLine(box);} // Driver codepublic static void Main(String []args){    int []size = { 1, 2, 3 };    int n = size.Length;         minBox(size, n);}} // This code is contributed by Amit Katiyar
<script> // javascript implementation to minimize the// number of the box by putting small// box inside the bigger one       // Function to minimize the countfunction minBox(arr,  n){          // Initial number of box    var box = n;      // Sort array of box size    // in increasing order    arr.sort();      var curr_box = 0, next_box = 1;    while (curr_box < n && next_box < n)    {                  // Check is current box size        // is smaller than next box size        if (arr[curr_box] < arr[next_box])        {                          // Decrement box count            // Increment current box count            // Increment next box count            box--;            curr_box++;            next_box++;        }          // Check if both box        // have same size        else if (arr[curr_box] ==                 arr[next_box])            next_box++;    }      // Print the result    document.write(box);}  // Driver code     var size = [ 1, 2, 3 ];    var n = size.length;          minBox(size, n);     </script>
1
Time Complexity: O(N*logN) as Arrays.sort() method is used.Auxiliary Space: O(1)
Approach: The key observation in the problem is that the minimum number of boxes is same as the maximum frequency of any element in the array. Because the rest of the elements are adjusted into one another.  Below is the illustration with the help of steps:
Create a Hash-map to store the frequency of the elements.
Finally, after maintaining the frequency return the maximum frequency of the element.
Below is the implementation of the above approach:
C++
Java
Python3
Javascript
// C++ implementation of the// above approach#include<bits/stdc++.h>using namespace std; // Function to count the boxes// at the endint countBoxes(vector<int>A) {         // Default value if    // array is empty    int count = -1;    int n = A.size();         // Map to store frequencies    unordered_map<int,int>Map;         // Loop to iterate over the    // elements of the array    for (int i=0; i<n; i++) {        int key = A[i];                     Map[key]++;         int val = Map[key];                 // Condition to get the maximum        // value of the key        if (val > count) count = val;             }             return count;}     // Driver Codeint main(){    vector<int>a = {8, 15, 1, 10, 5, 1};     // Function Call    int minBoxes = countBoxes(a);    cout<<minBoxes<<endl;} // This code is contributed by shinjanpatra.
// Java implementation of the// above approach import java.util.*; public class Boxes {       // Function to count the boxes    // at the end    int countBoxes(int[] A) {               // Default value if        // array is empty        int count = -1;        int n = A.length;                // Map to store frequencies        Map<Integer, Integer> map =          new HashMap<>();               // Loop to iterate over the        // elements of the array        for (int i=0; i<n; i++) {            int key = A[i];            map.put(key,              map.getOrDefault(key, 0) + 1);            int val = map.get(key);                       // Condition to get the maximum            // value of the key            if (val > count) count = val;        }        return count;    }         // Driver Code    public static void main(                  String[] args)    {        int[] a = {8, 15, 1, 10, 5, 1};        Boxes obj = new Boxes();               // Function Call        int minBoxes = obj.countBoxes(a);          System.out.println(minBoxes);    }}
# Python implementation of the# above approach # Function to count the boxes# at the enddef countBoxes(A):         # Default value if    # array is empty   count = -1   n = len(A)        # Map to store frequencies   map = {}        # Loop to iterate over the   # elements of the array   for i in range(n):      key = A[i]                   if(key in map):         map[key] = map[key]+1      else:         map[key] = 1       val = map[key]               # Condition to get the maximum      # value of the key      if (val > count):         count = val            return count     # Driver Codea = [8, 15, 1, 10, 5, 1] # Function CallminBoxes = countBoxes(a)print(minBoxes) # This code is contributed by shinjanpatra.
<script> // JavaScript implementation of the// above approach // Function to count the boxes// at the endfunction countBoxes(A) {         // Default value if    // array is empty    let count = -1;    let n = A.length;             // Map to store frequencies        let map = new Map();             // Loop to iterate over the        // elements of the array        for (let i=0; i<n; i++) {            let key = A[i];                         if(map.has(key)){                map.set(key,map.get(key)+1);            }            else map.set(key,1);             let val = map.get(key);                     // Condition to get the maximum            // value of the key            if (val > count) count = val;        }             return count;     }     // Driver Code let a = [8, 15, 1, 10, 5, 1]; // Function Calllet minBoxes = countBoxes(a);document.write(minBoxes,"</br>"); // This code is contributed by shinjanpatra.</script>
2
Time Complexity: O(N)Auxiliary Space: O(N)
SoumikMondal
amit143katiyar
divyeshrabadiya07
hrksom01
bunnyram19
shinjanpatra
Arrays
Competitive Programming
Greedy
Sorting
Arrays
Greedy
Sorting
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