Introduction

In this blog post, we will explore how to solve the LeetCode problem "715" using AI. LeetCode is a popular platform for preparing for coding interviews, and with the help of AI tools like Chatmagic, we can generate solutions quickly and efficiently - helping you pass the interviews and get the job offer without having to study for months.

Problem Statement

A Range Module is a module that tracks ranges of numbers. Design a data structure to track the ranges represented as half-open intervals and query about them. A half-open interval [left, right) denotes all the real numbers x where left <= x < right. Implement the RangeModule class: RangeModule() Initializes the object of the data structure. void addRange(int left, int right) Adds the half-open interval [left, right), tracking every real number in that interval. Adding an interval that partially overlaps with currently tracked numbers should add any numbers in the interval [left, right) that are not already tracked. boolean queryRange(int left, int right) Returns true if every real number in the interval [left, right) is currently being tracked, and false otherwise. void removeRange(int left, int right) Stops tracking every real number currently being tracked in the half-open interval [left, right). Example 1: Input ["RangeModule", "addRange", "removeRange", "queryRange", "queryRange", "queryRange"] [[], [10, 20], [14, 16], [10, 14], [13, 15], [16, 17]] Output [null, null, null, true, false, true] Explanation RangeModule rangeModule = new RangeModule(); rangeModule.addRange(10, 20); rangeModule.removeRange(14, 16); rangeModule.queryRange(10, 14); // return True,(Every number in [10, 14) is being tracked) rangeModule.queryRange(13, 15); // return False,(Numbers like 14, 14.03, 14.17 in [13, 15) are not being tracked) rangeModule.queryRange(16, 17); // return True, (The number 16 in [16, 17) is still being tracked, despite the remove operation) Constraints: 1 <= left < right <= 109 At most 104 calls will be made to addRange, queryRange, and removeRange.

Explanation

Here's a solution to the Range Module problem:

• Interval Management with Sorted List: Maintain a sorted list of non-overlapping intervals. This allows efficient searching and merging of intervals during addRange and removeRange operations.

• Binary Search for Interval Operations: Employ binary search to locate the positions where new intervals should be inserted, merged, or split during addRange and removeRange. This ensures logarithmic time complexity for these operations.

• Querying for Coverage: In the queryRange operation, use binary search to find the interval that might contain the query range's start. If such an interval exists and it completely covers the query range, return true; otherwise, return false.

• Runtime Complexity: O(N log N) where N is the number of intervals. Storage Complexity: O(N)

Code

    class RangeModule:
    def __init__(self):
        self.intervals = []

    def addRange(self, left: int, right: int) -> None:
        new_interval = [left, right]
        new_intervals = []
        i = 0
        while i < len(self.intervals) and self.intervals[i][1] < new_interval[0]:
            new_intervals.append(self.intervals[i])
            i += 1

        while i < len(self.intervals) and self.intervals[i][0] <= new_interval[1]:
            new_interval[0] = min(new_interval[0], self.intervals[i][0])
            new_interval[1] = max(new_interval[1], self.intervals[i][1])
            i += 1

        new_intervals.append(new_interval)

        while i < len(self.intervals):
            new_intervals.append(self.intervals[i])
            i += 1

        self.intervals = new_intervals

    def queryRange(self, left: int, right: int) -> bool:
        l, r = 0, len(self.intervals) - 1
        while l <= r:
            mid = (l + r) // 2
            if self.intervals[mid][0] <= left and self.intervals[mid][1] >= right:
                return True
            elif self.intervals[mid][1] < left:
                l = mid + 1
            else:
                r = mid - 1
        return False

    def removeRange(self, left: int, right: int) -> None:
        new_intervals = []
        i = 0
        while i < len(self.intervals) and self.intervals[i][1] <= left:
            new_intervals.append(self.intervals[i])
            i += 1

        while i < len(self.intervals) and self.intervals[i][0] < right:
            interval = self.intervals[i]
            if interval[0] < left:
                new_intervals.append([interval[0], left])
            if interval[1] > right:
                new_intervals.append([right, interval[1]])
            i += 1

        while i < len(self.intervals):
            new_intervals.append(self.intervals[i])
            i += 1

        self.intervals = new_intervals