20240108 Finished

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jackfiled 2024-01-08 23:55:55 +08:00
parent d4132e91d4
commit e36ae47792
2 changed files with 79 additions and 0 deletions

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@ -13,3 +13,4 @@ mod s0006_zigzag_conversion;
mod s0007_reverse_integer;
mod s0004_median_of_two_sorted_arrays;
mod s0743_network_delay_time;
mod s0447_number_of_boomerangs;

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@ -0,0 +1,78 @@
/**
* [447] Number of Boomerangs
*
* You are given n points in the plane that are all distinct, where points[i] = [xi, yi]. A boomerang is a tuple of points (i, j, k) such that the distance between i and j equals the distance between i and k (the order of the tuple matters).
* Return the number of boomerangs.
*
* <strong class="example">Example 1:
*
* Input: points = [[0,0],[1,0],[2,0]]
* Output: 2
* Explanation: The two boomerangs are [[1,0],[0,0],[2,0]] and [[1,0],[2,0],[0,0]].
*
* <strong class="example">Example 2:
*
* Input: points = [[1,1],[2,2],[3,3]]
* Output: 2
*
* <strong class="example">Example 3:
*
* Input: points = [[1,1]]
* Output: 0
*
*
* Constraints:
*
* n == points.length
* 1 <= n <= 500
* points[i].length == 2
* -10^4 <= xi, yi <= 10^4
* All the points are unique.
*
*/
pub struct Solution {}
// problem: https://leetcode.cn/problems/number-of-boomerangs/
// discuss: https://leetcode.cn/problems/number-of-boomerangs/discuss/?currentPage=1&orderBy=most_votes&query=
// submission codes start here
use std::collections::HashMap;
impl Solution {
pub fn number_of_boomerangs(points: Vec<Vec<i32>>) -> i32 {
let mut result = 0;
for p in &points {
let mut values = HashMap::new();
for q in &points {
let dis = (p[0] - q[0]).pow(2) + (p[1] - q[1]).pow(2);
let c = values.entry(dis).or_insert(0);
*c += 1;
}
for (_, v) in &values {
// 实际上并不需要因为最小值为1
// 计算的结果为0
if *v >= 2 {
// result += A_m^2
result += (*v) * (*v - 1);
}
}
}
result
}
}
// submission codes end
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_447() {
}
}