RECUR07 - Editorial

Problem Link - Print Pattern in Recursion

Problem Statement:

Given an integer N, we need to print an upside-down triangle of stars where the base of the triangle has N stars and each subsequent row contains one less star than the row above it.

Approach:

  • Loop through Rows:
    • Use a loop that starts from N and decrements down to 1.
    • For each iteration, print the corresponding number of stars.
  • Print Stars:
    • In each iteration, print a row of stars based on the current row number.

Complexity:

  • Time Complexity: O(N^2) . The total number of stars printed is N*(N+1)/2​, which results in O(N^2) total time due to the nested printing in each recursive call.
  • Space Complexity: O(N) due to the recursion stack. Each recursive call adds a new frame to the stack until the base case is reached.