Stream 中所有元素到达时按降序排列

给定一个数字流arr ，任务是在流中每个元素到达时按降序找到它们的排名。

Rank is defined as the total number of elements that is greater than the arriving element, where rank 1 defines the maximum value in the stream. Each value in the array is unique.

例子：

Input: arr = [88, 14, 69, 30, 29, 89] 
Output: 1 2 2 3 4 1 
Explanation: 
First 88 arrives, so its rank is 1. 
when 14 arrives, 14 is less than 88 so its rank is 2. 
when 69 arrives, 69 is less than 88 and greater than 14 so its rank is 2. 
when 30 arrives, 30 is less than 88 and 69 so its rank is 3. 
when 29 arrives, 29 is less than 88, 69, 30 than 29 so its rank is 4. 
when 89 arrives, 89 is greater than all values so its rank is 1. 
The rank of elements of array 1 2 2 3 4 1
Input: arr = [100, 110, 80, 85, 88, 89] 
Output: 1 1 3 3 3 3 
Explanation: 
First 100 arrive so its rank is 1. 
when 110 arrive, 110 is greater than 100 so its rank is 1. 
when 80 arrive, 80 is less than 110 and 100 so its rank is 3. 
when 85 arrive, 85 is less than 110 and 100 so its rank is 3. 
when 88 arrive, 88 is less than 110 and 100 so its rank is 3. 
when 89 arrive, 89 is less than 110 and 100 so its rank is 3. 
The rank of elements of array 1 1 3 3 3 3 
 

天真的方法：

1. 数组的第一个元素将始终具有排名 1。
2. 遍历数组，如果该元素在前面的元素中最大，则其秩为 1。
3. 如果元素不大于先前比较的元素。那么这个元素的排名将是它之前的更大元素的数量。
   例如，假设它大于 2 个先前的元素，则其等级为 3。

下面是上述方法的实现：

C++

// C++ program to rank of all elements
// in a Stream in descending order
// when they arrive
#include 
using namespace std;
     
    // FindRank function to find rank
        void FindRank(int arr[], int length)
    {
        // Rank of first element is always 1
        cout << "1" <<  " ";
         
        // Iterate over array
        for (int i = 1; i < length; i++)
        {
            // As element let say its rank is 1
            int rank = 1;
     
            // Element is compared
            // with previous elements
            for (int j = 0; j < i; j++)
            {
                // If greater than previous
                // than rank is incremented
                if(arr[j] > arr[i])
                    rank++;
                 
            }
             
            // print rank
            cout <<  rank  << " ";
        }
    }
 
 
 
 
// Driver code
int main() {
     
        // array named arr
        int arr[] = {88, 14, 69, 30, 29, 89};
     
        // length of arr
        int len = sizeof(arr)/sizeof(arr[0]);
     
        FindRank(arr, len);
         
    return 0;
}
 
// This code is contributed by AnkitRai01

Java

// Java program to rank of all elements
// in a Stream in descending order
// when they arrive
import java.util.*;
 
class GFG{
     
    // FindRank function to find rank
    static void FindRank(int arr[], int length)
    {
        // Rank of first element is always 1
        System.out.print("1" + " ");
         
        // Iterate over array
        for (int i = 1; i < arr.length; i++)
        {
            // As element let say its rank is 1
            int rank = 1;
     
            // Element is compared
            // with previous elements
            for (int j = 0; j < i; j++)
            {
                // If greater than previous
                // than rank is incremented
                if(arr[j] > arr[i])
                    rank++;
                 
            }
             
            // print rank
            System.out.print(rank + " ");
        }
    }
 
    // Driver code
    public static void main(String args[]){
         
        // array named arr
        int arr[] = {88, 14, 69, 30, 29, 89};
     
        // length of arr
        int len = arr.length;
     
        FindRank(arr, len);
    }
}
 
// This code is contributed by AbhiThakur

Python3

# Python program to rank of all elements
# in a Stream in descending order
# when they arrive
 
# FindRank function to find rank
def FindRank(arr, length):
     
    # Rank of first element is always 1
    print(1, end =" ")
     
    # Iterate over array
    for i in range(1, length):
         
        # As element let say its rank is 1
        rank = 1
 
        # Element is compared
        # with previous elements
        for j in range(0, i):
             
            # If greater than previous
            # than rank is incremented
            if(arr[j] > arr[i]):
                rank = rank + 1
                 
        # print rank
        print(rank, end =" ")
         
         
# Driver code
if __name__ == '__main__':
     
    # array named arr
    arr = [88, 14, 69, 30, 29, 89]
 
    # length of arr
    length = len(arr)
 
    FindRank(arr, length)

C#

// C# program to rank of all elements
// in a Stream in descending order
// when they arrive
using System;
 
class GFG{
     
    // FindRank function to find rank
    static void FindRank(int[] arr, int length)
    {
        // Rank of first element is always 1
        Console.Write("1" + " ");
         
        // Iterate over array
        for (int i = 1; i < arr.Length; i++)
        {
            // As element let say its rank is 1
            int rank = 1;
     
            // Element is compared
            // with previous elements
            for (int j = 0; j < i; j++)
            {
                // If greater than previous
                // than rank is incremented
                if(arr[j] > arr[i])
                    rank++;
                 
            }
             
            // print rank
            Console.Write(rank + " ");
        }
    }
 
    // Driver code
    public static void Main(){
         
        // array named arr
        int[] arr = {88, 14, 69, 30, 29, 89};
     
        // length of arr
        int len = arr.Length;
     
        FindRank(arr, len);
    }
}
 
// This code is contributed by AbhiThakur

Javascript

// javascript program to rank of all elements
// in a Stream in descending order
// when they arrive
 
    // FindRank function to find rank
    function FindRank(arr , length) {
        // Rank of first element is always 1
        document.write("1" + " ");
 
        // Iterate over array
        for (i = 1; i < arr.length; i++) {
            // As element let say its rank is 1
            var rank = 1;
 
            // Element is compared
            // with previous elements
            for (j = 0; j < i; j++) {
                // If greater than previous
                // than rank is incremented
                if (arr[j] > arr[i])
                    rank++;
 
            }
 
            // prvar rank
            document.write(rank + " ");
        }
    }
 
    // Driver code
     
 
        // array named arr
        var arr = [ 88, 14, 69, 30, 29, 89 ];
 
        // length of arr
        var len = arr.length;
 
        FindRank(arr, len);
 
// This code contributed by umadevi9616

输出：

1 2 2 3 4 1

时间复杂度： O(N ² ) ，其中 N 是数组的长度。
空间复杂度： O(1)
高效的方法：这个想法是使用二分搜索来找到数字的排名。它将给出大于给定数字的数字计数。
下面是上述方法的实现：

蟒蛇3

# Python program to rank of all elements
# in a Stream in descending order
# when they arrive
 
# import of bisect to use bisect.insort()
import bisect
 
# FindRank function to find rank
def FindRank(arr, length):
    # rank list to store values of
    # array in ascending order
    rank = []
 
    first = arr[0]
    rank.append(first)
    # Rank of first element is always 1
    print(1, end =" ")
     
    # Iterate over remaining array
    for i in range(1, length):
        val = arr[i]
         
        # element inserted in the rank list
        # using the binary method
         
        bisect.insort(rank, val)
         
        # To find rank of that element
         
        # length of rank array - index of element
        # in rank array
        eleRank = len(rank)-rank.index(val)
         
        # print of rank of element of array
        print(eleRank, end =" ")
 
# Driver code
if __name__ == '__main__':
     
    # array named arr
    arr = [88, 14, 69, 30, 29, 89]
 
    # lenght of arr
    length = len(arr)
 
    FindRank(arr, length)

输出：

1 2 2 3 4 1

时间复杂度： O(N * log N)，其中 N 是数组的长度。
空间复杂度： O(N)

如果您想与行业专家一起参加直播课程，请参阅Geeks Classes Live