LeetCode 1232. Dot into a line

topic

There the XY coordinate system in a number of points, we used the array coordinatesto their coordinates were recorded, where coordinates[i] = [x, y]abscissa is the xordinate of ythe point.

Please judge whether these points are on the same straight line in the coordinate system true, if yes, return , otherwise, please return false.

Example 1:

输入：coordinates = [[1,2],[2,3],[3,4],[4,5],[5,6],[6,7]]
输出：true

Example 2:

输入：coordinates = [[1,1],[2,2],[3,4],[4,5],[5,6],[7,7]]
输出：false

prompt:

• 2 <= coordinates.length <= 1000
• coordinates[i].length == 2
• -10^4 <= coordinates[i][0], coordinates[i][1] <= 10^4
• coordinates Does not contain duplicate points

Source: LeetCode (LeetCode)
Link: https://leetcode-cn.com/problems/check-if-it-is-a-straight-line
Copyright is owned by LeetCode . For commercial reprints, please contact the official authorization. For non-commercial reprints, please indicate the source.

answer

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

0ms 38MB
Because of division reasons, it is impossible to have 0, so I found a formula deduced by others on the Internet, fixed two points, and then input the coordinates of the third point to determine whether it is the same straight line

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