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When working with multiple strings, we often need to find specific substrings from the union of all possible substrings. This involves generating all substrings from each string, creating a sorted union set, and retrieving elements at specified positions. So, if the input strings are ['pqr', 'pqt'] and queries are [4, 7, 9], then the output will be ['pqt', 'qt', 't']. How It Works The substrings from the first string are: {p, pq, pqr, q, qr, r} The substrings from the second string are: {p, pq, pqt, q, qt, t} The union of these sets is: {p, ... Read More
In a regular polygon with n sides, we need to count isosceles triangles formed by vertices of the same color. The vertices are colored either blue (0) or red (1) represented as a binary string. An isosceles triangle has at least two sides of equal length. So, if the input is like polygon = "111010", then the output will be 2 because there are two triangles ACE and AFE as shown in the diagram ? A(1) B(1) ... Read More
When working with string matching problems, we often need to find substrings that either match exactly or differ by only one character. This article demonstrates how to find starting indexes in a string where substrings match another string completely or differ at exactly one position. Given two strings where the first string is longer than the second, we need to identify all starting positions where substrings from the first string either match the second string exactly or differ by only one character. Problem Example If we have string1 = 'tpoint' and string2 = 'pi', the output should ... Read More
We need to find the maximum possible value of an expression (sum1)² + (sum2)² where sum1 and sum2 are sums of elements from non-empty subsets of two arrays nums1 and nums2. Given two arrays with the same number of elements, we select indices and calculate the sum of corresponding elements from each array, then find the maximum value of the sum of their squares. Problem Understanding For arrays nums1 = [-1, 6] and nums2 = [5, 4], possible calculations are ? Using index 0: (-1)² + (5)² = 1 + 25 = 26 Using index ... Read More
In this problem, we need to find the similarity between a string and all its suffixes. The similarity is defined as the length of the longest common prefix between the original string and each suffix. We then sum up all these similarities. For example, if the string is 'abcd', the suffixes are 'abcd', 'bcd', 'cd', 'd'. We compare each suffix with the original string to find how many characters match from the beginning. Understanding the Problem Let's see how this works with the string 'tpotp' ? Original string: 'tpotp' Suffixes and their similarities: 'tpotp' → ... Read More
Suppose, we are given a string input_str. We need to find all possible substrings from the given string, then concatenate all the substrings in lexicographic order into another string. Given an integer value k, our task is to return the letter at index k from the concatenated string. So, if the input is like input_str = 'pqrs', k = 6, then the output will be 'p'. Understanding the Problem The substrings from the given string 'pqrs' in lexicographic order are: p, pq, pqr, pqrs, q, qr, qrs, r, rs, s. If we concatenate these strings, it ... Read More
Creating curved text in a polar plot requires plotting lines along curved paths and positioning text elements along angular coordinates. This technique is useful for creating circular labels, curved annotations, and artistic text layouts in matplotlib polar plots. Basic Setup First, let's create a basic polar plot with curved lines ? import matplotlib.pyplot as plt import numpy as np from scipy.interpolate import interp1d plt.rcParams["figure.figsize"] = [8, 6] plt.rcParams["figure.autolayout"] = True fig = plt.figure() ax = fig.add_subplot(111, projection="polar") # Create radial lines at specific angles for degree in [0, 90, 180, 270]: ... Read More
In Matplotlib, plt.figure() and plt.subplots() are two fundamental functions for creating plots, but they serve different purposes and return different objects. Understanding plt.figure() plt.figure() creates a new figure object or activates an existing one. It returns a Figure object but doesn't create any axes by default. import matplotlib.pyplot as plt import numpy as np # Create a figure using plt.figure() fig = plt.figure(figsize=(8, 5)) fig.suptitle("Using plt.figure()") # Add data manually using plt.plot() x = np.linspace(0, 10, 50) y = np.sin(x) plt.plot(x, y, 'b-', label='sin(x)') plt.xlabel('X values') plt.ylabel('Y values') plt.legend() plt.grid(True) plt.show() ... Read More
Given a number n, we need to find all possible permutations of positive integers up to n, sort them lexicographically, and number them from 1 to n!. When some values in a "special permutation" are forgotten (replaced with 0s), we must find all permutations that could match the original and sum their lexicographic positions. For example, if the special permutation is [0, 2, 0] with n=3, the possible original permutations are [1, 2, 3] (position 2) and [3, 2, 1] (position 5), giving us a sum of 7. Algorithm Steps The solution uses factorial number system and ... Read More
In Matplotlib, you can capture mouse click coordinates on a plot by connecting an event handler to the figure's canvas. This is useful for interactive data exploration and annotation. Setting Up Mouse Click Detection The key is to use mpl_connect() to bind a function to the 'button_press_event' ? import numpy as np import matplotlib.pyplot as plt plt.rcParams["figure.figsize"] = [7.00, 3.50] plt.rcParams["figure.autolayout"] = True def mouse_event(event): if event.xdata is not None and event.ydata is not None: print('x: {:.3f} and y: {:.3f}'.format(event.xdata, event.ydata)) ... Read More