74 lines
1.9 KiB
Rust
74 lines
1.9 KiB
Rust
/**
|
|
* [1] Two Sum
|
|
*
|
|
* Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target.
|
|
* You may assume that each input would have exactly one solution, and you may not use the same element twice.
|
|
* You can return the answer in any order.
|
|
*
|
|
* <strong class="example">Example 1:
|
|
*
|
|
* Input: nums = [2,7,11,15], target = 9
|
|
* Output: [0,1]
|
|
* Explanation: Because nums[0] + nums[1] == 9, we return [0, 1].
|
|
*
|
|
* <strong class="example">Example 2:
|
|
*
|
|
* Input: nums = [3,2,4], target = 6
|
|
* Output: [1,2]
|
|
*
|
|
* <strong class="example">Example 3:
|
|
*
|
|
* Input: nums = [3,3], target = 6
|
|
* Output: [0,1]
|
|
*
|
|
*
|
|
* Constraints:
|
|
*
|
|
* 2 <= nums.length <= 10^4
|
|
* -10^9 <= nums[i] <= 10^9
|
|
* -10^9 <= target <= 10^9
|
|
* Only one valid answer exists.
|
|
*
|
|
*
|
|
* Follow-up: Can you come up with an algorithm that is less than O(n^2)<font face="monospace"> </font>time complexity?
|
|
*/
|
|
pub struct Solution {}
|
|
|
|
// problem: https://leetcode.cn/problems/two-sum/
|
|
// discuss: https://leetcode.cn/problems/two-sum/discuss/?currentPage=1&orderBy=most_votes&query=
|
|
|
|
// submission codes start here
|
|
|
|
use std::collections::HashMap;
|
|
impl Solution {
|
|
pub fn two_sum(nums: Vec<i32>, target: i32) -> Vec<i32> {
|
|
let mut map = HashMap::with_capacity(nums.len());
|
|
|
|
for (index, value) in nums.iter().enumerate() {
|
|
match map.get(&(target - value)) {
|
|
None => {
|
|
map.insert(value, index);
|
|
}
|
|
Some(target_index) => {
|
|
return vec![*target_index as i32, index as i32];
|
|
}
|
|
}
|
|
}
|
|
|
|
vec![]
|
|
}
|
|
}
|
|
|
|
// submission codes end
|
|
|
|
#[cfg(test)]
|
|
mod tests {
|
|
use super::*;
|
|
|
|
#[test]
|
|
fn test_1() {
|
|
assert_eq!(vec![0, 1], Solution::two_sum(vec![2, 7, 11, 15], 9));
|
|
assert_eq!(vec![1, 2], Solution::two_sum(vec![3, 2, 4], 6));
|
|
}
|
|
}
|