1232. Check If It Is a Straight Line

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.

Examples

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

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

Solution for 1232. Check If It Is a Straight Line Problem

Approach

1. Calculate the Initial Slope:

   • Compute the difference in the y values (diff_y) and the difference in the x values (diff_x) between the first two points.

2. Iterate through the Points:

   • For each subsequent point, compute the product of the initial slope differences with the current point's differences.
   • If at any point the calculated products do not match, the points do not lie on a straight line.

3. Return the Result:

   • If all points satisfy the condition, return true. Otherwise, return false.

Solution

Implementation

Live Editor

function Solution(arr) {
    function checkStraightLine(coordinates) {
    const diff_y = (coordinates[1][1] - coordinates[0][1]);
    const diff_x = (coordinates[1][0] - coordinates[0][0]);
    for (let i = 2; i < coordinates.length; i++) {
        if (diff_y * (coordinates[i][0] - coordinates[i-1][0]) !== diff_x * (coordinates[i][1] - coordinates[i-1][1])) {
            return false;
        }
    }
    return true;
}
  const input =  [[1,2],[2,3],[3,4],[4,5],[5,6],[6,7]]
  const output = checkStraightLine(input)
  return (
    <div>
      <p>
        <b>Input: </b>
        {JSON.stringify(input)}
      </p>
      <p>
        <b>Output:</b> {output.toString()}
      </p>
    </div>
  );
}

Result

Loading...

Complexity Analysis

• Time Complexity: $O(N)$
• Space Complexity: $O(1)$

Code in Different Languages

JavaScript

Written by @hiteshgahanolia

 function  checkStraightLine(coordinates) {
     const diff_y = (coordinates[1][1] - coordinates[0][1]);
     const diff_x = (coordinates[1][0] - coordinates[0][0]);
     for (let i = 2; i < coordinates.length; i++) {
         if (diff_y * (coordinates[i][0] - coordinates[i-1][0]) !== diff_x * (coordinates[i][1] - coordinates[i-1][1])) {
             return false;
         }
     }
     return true;
 }

TypeScript

Written by @hiteshgahanolia

class Solution {
 checkStraightLine(coordinates: number[][]): boolean {
     const diff_y = (coordinates[1][1] - coordinates[0][1]);
     const diff_x = (coordinates[1][0] - coordinates[0][0]);
     for (let i = 2; i < coordinates.length; i++) {
         if (diff_y * (coordinates[i][0] - coordinates[i-1][0]) !== diff_x * (coordinates[i][1] - coordinates[i-1][1])) {
             return false;
         }
     }
     return true;
 }
}

Python

Written by @hiteshgahanolia

class Solution:
 def checkStraightLine(self, coordinates: List[List[int]]) -> bool:
     diff_y = (coordinates[1][1] - coordinates[0][1])
     diff_x = (coordinates[1][0] - coordinates[0][0])
     for i in range(2, len(coordinates)):
         if diff_y * (coordinates[i][0] - coordinates[i-1][0]) != diff_x * (coordinates[i][1] - coordinates[i-1][1]):
             return False
     return True

Java

Written by @hiteshgahanolia

import java.util.List;

class Solution {
 public boolean checkStraightLine(List<int[]> coordinates) {
     int diff_y = (coordinates.get(1)[1] - coordinates.get(0)[1]);
     int diff_x = (coordinates.get(1)[0] - coordinates.get(0)[0]);
     for (int i = 2; i < coordinates.size(); i++) {
         if (diff_y * (coordinates.get(i)[0] - coordinates.get(i-1)[0]) != diff_x * (coordinates.get(i)[1] - coordinates.get(i-1)[1])) {
             return false;
         }
     }
     return true;
 }
}

C++

Written by @hiteshgahanolia

class Solution {
public:
 bool checkStraightLine(vector<vector<int>>& coordinates) {
     int diff_y = (coordinates[1][1] - coordinates[0][1]);
     int diff_x = (coordinates[1][0] - coordinates[0][0]);
     for(int i=2; i<coordinates.size(); i++)
     {
         if(diff_y*(coordinates[i][0] - coordinates[i-1][0]) != diff_x*(coordinates[i][1] - coordinates[i-1][1]))
             return false;
     }
     return true;
 }
};

References

• LeetCode Problem: Check If It Is a Straight Line

• Solution Link: LeetCode Solution