1232. Check If It Is a Straight Line Easy

1/**
2 * [1232] Check If It Is a Straight Line
3 *
4 * 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.
5 *
6 *  
7 *
8 *  
9 * Example 1:
10 *
11 * <img alt="" src="https://assets.leetcode.com/uploads/2019/10/15/untitled-diagram-2.jpg" style="width: 336px; height: 336px;" />
12 *
13 *
14 * Input: coordinates = [[1,2],[2,3],[3,4],[4,5],[5,6],[6,7]]
15 * Output: true
16 *
17 *
18 * Example 2:
19 *
20 * <img alt="" src="https://assets.leetcode.com/uploads/2019/10/09/untitled-diagram-1.jpg" style="width: 348px; height: 336px;" />
21 *
22 *
23 * Input: coordinates = [[1,1],[2,2],[3,4],[4,5],[5,6],[7,7]]
24 * Output: false
25 *
26 *
27 *  
28 * Constraints:
29 *
30 *
31 * 2 <= coordinates.length <= 1000
32 * coordinates[i].length == 2
33 * -10^4 <= coordinates[i][0], coordinates[i][1] <= 10^4
34 * coordinates contains no duplicate point.
35 *
36 */
37pub struct Solution {}
38
39// problem: https://leetcode.com/problems/check-if-it-is-a-straight-line/
40// discuss: https://leetcode.com/problems/check-if-it-is-a-straight-line/discuss/?currentPage=1&orderBy=most_votes&query=
41
42// submission codes start here
43
44impl Solution {
45    pub fn check_straight_line(coordinates: Vec<Vec<i32>>) -> bool {
46        if coordinates.len() < 3 {
47            return true;
48        }
49
50        let good = |v: &Vec<i32>| {
51            (coordinates[1][0] - coordinates[0][0]) as i128 * (v[1] - coordinates[0][1]) as i128
52                == (coordinates[1][1] - coordinates[0][1]) as i128
53                    * (v[0] - coordinates[0][0]) as i128
54        };
55
56        for i in 2..coordinates.len() {
57            if !good(&coordinates[i]) {
58                return false;
59            }
60        }
61        true
62    }
63}
64
65// submission codes end
66
67#[cfg(test)]
68mod tests {
69    use super::*;
70
71    #[test]
72    fn test_1232() {
73        assert!(Solution::check_straight_line(vec![
74            vec![1, 2],
75            vec![2, 3],
76            vec![3, 4],
77            vec![4, 5],
78            vec![5, 6],
79            vec![6, 7]
80        ]));
81    }
82}
83