Study Notes
  • Kuma Blog
  • AI
    • AI-Resources
    • AI-books
    • AI_Blogs
      • Exploring the Future of AI in 2025: Key Trends and Predictions
      • Exploring the Power of Kuma AI Tools in 2025
      • The Future of AI in 2025: Predicting the Next Big Trends
      • The Future of AI in 2025: Predictions and Insights
      • The Future of AI in 2025: Trends and Predictions
      • The-Future-of-AI-in-2025-Trends-to-Watch_2025-05-30
      • Untitled-1748347240822_2025-05-27
      • Untitled-1748520038559_2025-05-29
    • Kuma_AI_Daily_NewsLetter
      • Kuma AI Daily News Letter 2025-05-25
      • Kuma AI Daily News Letter 2025-05-26
      • Kuma AI Daily News Letter 2025-05-27
      • Kuma AI Daily News Letter 2025-05-28
      • Kuma AI Daily News Letter 2025-05-29
      • Kuma AI Daily News Letter 2025-05-30
      • Kuma AI Daily News Letter 2025-05-31
    • Prompts
      • Prompts Free Courses
    • AI_Agents
      • Kuma AI Travel Agent
        • Kuma AI Travel Agent
  • Movies
    • 2024
    • 2024
    • 2024
  • Google
    • chunked-palindrome
  • Setup
    • How to add a new user into Ubuntu and setup ssh key?
    • How to set up VSCode remote server connect with browser with Docker
  • kubernetes
  • Books
    • Designing-Data-Intensive-Applications
      • 第一章 — 可靠性,可扩展性,可维护性的应用程序(Reliable, Scalable, and Maintainable Applications)
    • System-Performance
      • Design-Data-Intensive-Application
      • Chapter 2: Methodologies
  • Languages
    • japanese
      • japanese-week
  • Leetcode
    • 30DayChallenge
      • LRU-cache
      • backspace-string-compare
      • binary-tree-maximum-path-sum
      • bitwise-and-number-range
      • check-string-valid-sequence-from-root-to-leaves-path-in-bst
      • construct-binary-search-tree-from-preorder-traversal
      • contiguous-array
      • counting-elements
      • diameter-of-binary-tree
      • first-unique-number
      • group-anagrams
      • jump-game
      • last-stone-weight
      • leftmost-column-with-at-least-a-one
      • longest-common-subsequect
      • maximal-square
      • maximum-subarray
      • middle-of-the-linked-list
      • min-stack
      • minimun-path-sum
      • move-zeroes
      • perform-string-shifts
      • product-of-array-except-itself
      • search-in-rotated-sorted-array
      • subarray-sum-equals-k
      • valid-parenthesis-string
    • English Solution
      • 1168.optimize-water-distribution-in-a-village-en
      • 1171.remove-zero-sum-consecutive-nodes-from-linked-list-en
      • 1177.can-make-palindrome-from-substring-en
      • 1343.number-of-avg-subarr-sizek-greater-or-equal-threshold
      • 1345.jump-game-iv
      • 25.reverse-nodes-in-k-groups-en
      • 474.ones-and-zeros-en
      • 53.maximum-sum-subarray-en
      • 547.friend-circles-en
      • 79.word-search-en
    • May2020Challenge
      • check-if-straight-line
      • cousins-in-binary-tree
      • find-town-judge
      • first-bad-version
      • first-unique-character-in-a-string
      • flood-fill
      • implement-trie
      • jewels-and-stones
      • majority-element
      • maximum-sum-circular-subarray
      • number-complement
      • odd-even-linkedlist
      • ransom-note
      • remove-k-digits
      • single-element-in-sorted-array
      • valid-perfect-square
    • python
      • 000017-Letter-Combinations-of-a-Phone-Number
      • 000032-Longest-Valid-Parentheses
      • 000033-Search-in-Rotated-Sorted-Array
      • 000046-Permutations
      • 000074-Search-a-2D-Matrix
      • 000077-Combinations
      • 000081-Search-in-Rotated-Sorted-Array-II
      • 000137-single-number-ii
      • 000139-Word-Break
      • 000207-courses-schedule
      • 000209-Minimum-Size-Subarray-Sum
      • 000376-wiggle-subsequence
      • 000445-Add-Two-Numbers-II
      • 000486-Predict-the-Winner
      • 000518-Coin-Change-II
      • 000673-Number-of-Longest-Increasing-Subsequence
      • 000688-Knight-Probability-in-Chessboard
      • 000735-Asteroid-Collision
      • 000852-Peak-Index-in-a-Mountain-Array
      • 859-Buddy-Strings
      • 000864-Shortest-Path-to-Get-All-Keys
      • 000920-Number-of-Music-Playlists
      • 001218-Longest-Arithmetic-Subsequence-of-Given-Difference
      • 001235-Maximum-Profit-in-Job-Scheduling
      • 001493-Longest-Subarray-of 1-After-Deleting-One-Element
      • Problem
      • 002024-Maximize-the-Confusion-of-an-Exam
      • 2305-Fair-Distribution-of-Cookies
      • 002616-Minimize-the-Maximum-Difference-of-Pairs
      • 00802-Find-Eventual-Safe-States
    • 中文版解题
      • 1147.longest-chunked-palindrome-decomposition-cn
      • 1168.optimize-water-distribution-in-a-village-cn
      • 1171.remove-zero-sum-consecutive-nodes-from-linked-list-cn
      • 1177.can-make-palindrome-from-substring-cn
      • 215.kth-largest-element-in-an-array-cn
      • 25.reverse-nodes-in-k-groups-cn
      • 30.substring-with-concatenation-of-all-words-cn
      • 4.median-of-two-sorted-array-cn
      • 460.LFU-cache-cn
      • 474.ones-and-zeros-cn
      • 53.maximum-sum-subarray-cn
      • 79.word-search-cn
  • Readings
    • 2020
      • Design-Data-Intensive-Application
      • 亲爱的提奥
      • 理想国
      • 贫穷的本质
Powered by GitBook
On this page
  • Problem
  • Problem Description
  • Solution
  • Complexity Analysis
  • Code

Was this helpful?

  1. Leetcode
  2. May2020Challenge

check-if-straight-line

PreviousMay2020ChallengeNextcousins-in-binary-tree

Last updated 5 years ago

Was this helpful?

Problem

Problem Description

You are given an array coordinates, coordinates[i] = [x, y], where [x, y] represents the coordinate of a point. Check if these points make a straight line in the XY plane.

Example 1:

Input: coordinates = [[1,2],[2,3],[3,4],[4,5],[5,6],[6,7]]
Output: true

Example 2:
Input: coordinates = [[1,1],[2,2],[3,4],[4,5],[5,6],[7,7]]
Output: false


 Constraints:

 1. 2 <= coordinates.length <= 1000
 2. coordinates[i].length == 2
 3. -10^4 <= coordinates[i][0], coordinates[i][1] <= 10^4
 4. coordinates contains no duplicate point.

Solution

This problem is a math problem, how to calculate slope for any two points.

for 2 points: X(x1, y1), Y(x2, y2), slope = (y1 - y2) / (x1 - x2)

Then this problem can seen as calculate every two points slope and compare all the slopes. if slopes are the same, then all points are in the same line, otherwise not in the same line.

For example:

Complexity Analysis

Time Complexity: O(N)

Space Complexity: O(N)

  • N - Max (ransom note length, magazine length)

Code

class Solution {
    public boolean checkStraightLine(int[][] coordinates) {
        int len = coordinates.length;
        int[] first = coordinates[0];
        int[] second = coordinates[1];
        // calculate slope of first and second points, slope = (y2-y1)/(x2-x1)
        double slope = (double)(first[1] - second[1]) / (first[0] - second[0]);
        // check every two points slope and compare with slope, if not same, then not in a line, terminate, return false.
        for (int i = 2; i < len; i++) {
            in[] curr = coordicates[i];
            if ((double)(first[1] - curr[1]) / (first[0] - curr[0]) != slope) {
                return false;
            }
        }
        // if already check all point, and all have the same slope, in the same line.
        return true;
    }
}
Check If It Is a Straight Line
Check If It is a Straight Line