leetcode 18 rust

题目

编程语言

rust

注意点

同leetcode15

代码

pub fn four_sum(nums: Vec<i32>, target: i32) -> Vec<Vec<i32>> {
    let mut res : Vec<Vec<i32>> = Vec::new();
    if nums.len() < 4 {
        return res;
    }
    let mut nums2 = nums.clone();
    nums2.sort();
    if nums2[0] > 0 {
        return res;
    }
    for i in 0..(nums2.len()-3) {
        if i > 0 && nums2[i] == nums2[i-1] {
            continue;
        }
        for j in (i+1)..(nums2.len()-2) {
            if j > i+1 && nums2[j] == nums2[j-1] {
                continue;
            }
            let mut l = j+1;
            let mut r = nums2.len()-1;
            while l < r {
                let sum = nums2[i] + nums2[j] + nums2[l] + nums2[r];
                match sum.cmp(&target) {
                    std::cmp::Ordering::Equal => {
                        res.push(vec![nums2[i],nums2[j],nums2[l],nums2[r]]);
                        while l < r && nums2[l] == nums2[l+1] {
                            l = l + 1;
                        }
                        while l < r && nums2[r] == nums2[r-1] {
                            r = r - 1;
                        }
                        l = l + 1;
                        r = r - 1;
                    },
                    std::cmp::Ordering::Less => {
                        l = l + 1;
                    },
                    std::cmp::Ordering::Greater => {
                        r = r - 1;
                    }
                }
            }
        }
    }
    res
}

测试

#[cfg(test)]
mod tests{
    use super::*;
    #[test]
    fn test_1(){
        assert_eq!(four_sum(vec![1,0,-1,0,-2,2],0),vec![vec![-2,-1,1,2],vec![-2,0,0,2],vec![-1,0,0,1]]);
    }
    #[test]
    fn test_2(){
        assert_eq!(four_sum(vec![],0),Vec::<Vec<i32>>::new());
    }
}