2022-06-29：x = { a, b, c, d }，
y = { e, f, g, h }，
x、y两个小数组长度都是4。
如果有: a + e = b + f = c + g = d + h，
那么说x和y是一个完美对。
题目给定N个小数组，每个小数组长度都是K。
返回这N个小数组中，有多少完美对。
来自阿里。
答案2022-06-29：
找特征，存map，求数组相邻数字的差值，组装成key，value是数量。
代码用rust编写。代码如下：
use std::collections::HashMap;
fn main() {
let sc: Vec<i32> = vec![5, 3, 2, 11, 21, 19, 10, 1, 20, 11, 1, 6, 15, 24, 18, 27, 36];
let mut ii: i32 = 0;
while ii < sc.len() as i32 {
let n = sc[ii as usize];
ii += 1;
let m: i32 = sc[ii as usize];
ii += 1;
let mut matrix: Vec<Vec<isize>> = vec![];
for i in 0..n {
matrix.push(vec![]);
for _ in 0..m {
matrix[i as usize].push(sc[ii as usize] as isize);
ii += 1;
}
}
println!("matrix = {:?}", matrix);
let ans = perfect_pairs(&mut matrix);
println!("ans = {}", ans);
}
}
fn perfect_pairs(matrix: &mut Vec<Vec<isize>>) -> isize {
let mut ans: isize = 0;
// key : 字符串 特征，差值特征 : "_5_-2_6_9"
let mut counts: HashMap<String, isize> = HashMap::new();
for arr in matrix.iter() {
let mut self0: String = String::new();
let mut minus: String = String::new();
for i in 1..arr.len() as isize {
self0.push_str(
&(String::from("_") + &format!("{}", arr[i as usize] - arr[(i - 1) as usize])),
);
minus.push_str(
&(String::from("_") + &format!("{}", arr[(i - 1) as usize] - arr[i as usize])),
);
}
ans += match counts.get(&minus) {
Some(v) => *v,
None => 0,
};
counts.insert(
self0.clone(),
match counts.get(&self0) {
Some(v) => (*v) + 1,
None => 1,
},
);
}
return ans;
}
执行结果如下：
左神java代码