Welcome to Subscribe On Youtube

Formatted question description: https://leetcode.ca/all/1232.html

1232. Check If It Is a Straight Line (Easy)

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:

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

Related Topics:
Array, Math, Geometry

Solution 1.

• Java
• C++
• Python
• Go

• class Solution {
      public boolean checkStraightLine(int[][] coordinates) {
          int length = coordinates.length;
          if (length == 2)
              return true;
          int deltaX = coordinates[1][0] - coordinates[0][0], deltaY = coordinates[1][1] - coordinates[0][1];
          for (int i = 2; i < length; i++) {
              int curDeltaX = coordinates[i][0] - coordinates[i - 1][0], curDeltaY = coordinates[i][1] - coordinates[i - 1][1];
              if (deltaX * curDeltaY != deltaY * curDeltaX)
                  return false;
          }
          return true;
      }
  }
  
  ############
  
  class Solution {
      public boolean checkStraightLine(int[][] coordinates) {
          int x1 = coordinates[0][0], y1 = coordinates[0][1];
          int x2 = coordinates[1][0], y2 = coordinates[1][1];
          for (int i = 2; i < coordinates.length; ++i) {
              int x = coordinates[i][0], y = coordinates[i][1];
              if ((x - x1) * (y2 - y1) != (y - y1) * (x2 - x1)) {
                  return false;
              }
          }
          return true;
      }
  }
  

• // OJ: https://leetcode.com/problems/check-if-it-is-a-straight-line/
  // Time: O(N)
  // Space: O(1)
  class Solution {
  public:
      bool checkStraightLine(vector<vector<int>>& A) {
          int N = A.size(), x1 = A[0][0], y1 = A[0][1], x2 = A[1][0], y2 = A[1][1];
          for (int i = 2; i < N; ++i) {
              if ((A[i][1] - y1) * (x2 - x1) != (y2 - y1) * (A[i][0] - x1)) return false;
          }
          return true;
      }
  };
  

• class Solution:
      def checkStraightLine(self, coordinates: List[List[int]]) -> bool:
          x1, y1 = coordinates[0]
          x2, y2 = coordinates[1]
          for x, y in coordinates[2:]:
              if (x - x1) * (y2 - y1) != (y - y1) * (x2 - x1):
                  return False
          return True
  
  ############
  
  # 1232. Check If It Is a Straight Line
  # https://leetcode.com/problems/check-if-it-is-a-straight-line/
  
  class Solution:
      def checkStraightLine(self, coordinates: List[List[int]]):
          (x0,y0), (x1,y1) = coordinates[:2]
          
          return all((x1-x0) * (y-y1) == (x-x1) * (y1-y0) for x,y in coordinates)
  

• func checkStraightLine(coordinates [][]int) bool {
  	x1, y1 := coordinates[0][0], coordinates[0][1]
  	x2, y2 := coordinates[1][0], coordinates[1][1]
  	for i := 2; i < len(coordinates); i++ {
  		x, y := coordinates[i][0], coordinates[i][1]
  		if (x-x1)*(y2-y1) != (y-y1)*(x2-x1) {
  			return false
  		}
  	}
  	return true
  }
  

All Problems

All Solutions