python - 线性搜索给定数组以给出所需的元素索引

Question

我已经在 Python3 中编写了线性搜索代码，但我没有得到所需的输出。问题如下:

You have been given an array of size N consisting of integers. In addition you have been given an element M you need to find and

print the index of the last occurrence of this element M in the array if it exists in it, otherwise print -1. Consider this array to be 1 indexed.

Input Format: The first line consists of 2 integers N and M denoting the size of the array and the element to be searched for in the array respectively .

The next line contains N space separated integers denoting the elements of of the array. Output Format Print a single integer denoting the index of the last occurrence of integer M in the array if it exists, otherwise print -1.

SAMPLE INPUT
5 1

1 2 3 4 1

SAMPLE OUTPUT
5

arr_len , num = input("Enter length & no to be search: ").split()
#num = int(input("Enter number to search: "))
list_of_elements = list(map(int, input("Enter array to search: ").split()))
found = False
for i in range(len(list_of_elements)):
 temp = list_of_elements[i]
 if(temp == num):
  print('--IF cond working--')
  found = True
  print("%d found at %dth position"%(num,i+1))
  break

if(found == False):
 print("-1")

在这里查看我的代码 ( https://ide.geeksforgeeks.org/FSYpglmfnz )

我不明白为什么 if 条件在 for 循环中不起作用

Answer 1

要找到最后的位置，您可以向后搜索并在第一次命中时停止:

arr_len, num = 6, 1                    # Test Data
list_of_elements = [1, 2, 3, 4, 1, 6]  # Test Data

pos = -1  # initial pos (not found)
for i in range(arr_len, 0, -1):        # 6,5,4,3,2,1
    temp = list_of_elements[i-1]       # adjust for 0-based index
    if(temp == num):
        pos = i # Store position where num is found
        break

print(pos)