Merge pull request neetcode-gh#1299 from zim0369/3sum

Update 15-3sum.rs

rust/15-3sum.rs

@@ -1,44 +1,61 @@
+use std::cmp::Ordering::{Equal, Greater, Less};
+
 impl Solution {
- pub fn three_sum(mut nums: Vec<i32>) -> Vec<Vec<i32>> {
- nums.sort_unstable();
-
- let mut res = vec![];
-
- for i in 0..nums.len() - 1{
- let n1 = nums[i];
-
- if i > 0 && n1 == nums[i - 1]{
+ pub fn three_sum(mut numbers: Vec<i32>) -> Vec<Vec<i32>> {
+ numbers.sort_unstable();
+
+ let mut ans: Vec<Vec<i32>> = Vec::new();
+
+ for i in 0..numbers.len() {
+ if i > 0 && numbers[i] == numbers[i - 1] {
  continue;
  }
-
- let (mut l, mut r) = (i + 1, nums.len() - 1);
-
- while l < r{
- let n2 = nums[l];
- let n3 = nums[r];
-
- let sum = n1 + n2 + n3;
-
- if sum > 0{
- r-=1;
- }else if sum < 0{
- l+=1;
- }else{
- res.push(vec![n1, n2, n3]);
-
- while l < r && n2 == nums[l + 1]{
- l+=1;
- }
- l+=1;
-
- while l < r && n3 == nums[r - 1]{
- r-=1;
+
+ let (mut l, mut r) = (i + 1, numbers.len() - 1);
+
+ while l < r {
+ match (numbers[i] + numbers[l] + numbers[r]).cmp(&0) {
+ Less => l += 1,
+ Greater => r -= 1,
+ Equal => {
+ ans.push(vec![numbers[i], numbers[l], numbers[r]]);
+ l += 1;
+ while numbers[l] == numbers[l - 1] && l < r {
+ l += 1;
+ }
+ r -= 1;
+ while numbers[r] == numbers[r + 1] && l < r {
+ r -= 1;
+ }
  }
- r-=1;
  }
  }
  }
- 
- res
+
+ ans
  }
-}
+}
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