rustgym/leetcode/
_43_multiply_strings.rs

1struct Solution;
2
3impl Solution {
4    fn multiply(num1: String, num2: String) -> String {
5        let n1 = num1.len();
6        let n2 = num2.len();
7        let n3 = n1 + n2;
8        let mut v1: Vec<i32> = vec![0; n1];
9        let mut v2: Vec<i32> = vec![0; n2];
10        let mut v3: Vec<i32> = vec![0; n3];
11        let mut v4: Vec<i32> = vec![];
12        for (i, c) in num1.char_indices() {
13            v1[n1 - 1 - i] = (c as u8 - b'0') as i32;
14        }
15        for (i, c) in num2.char_indices() {
16            v2[n2 - 1 - i] = (c as u8 - b'0') as i32;
17        }
18        for i in 0..n1 {
19            for j in 0..n2 {
20                v3[i + j] += v1[i] * v2[j];
21            }
22        }
23        let mut carry = 0;
24        for i in 0..n3 {
25            v4.push((v3[i] + carry) % 10);
26            carry = (v3[i] + carry) / 10;
27        }
28        if carry != 0 {
29            v4.push(carry);
30        }
31        while let Some(0) = v4.last() {
32            v4.pop();
33        }
34        v4.reverse();
35        if v4.is_empty() {
36            "0".to_string()
37        } else {
38            v4.into_iter().map(|x| (x as u8 + b'0') as char).collect()
39        }
40    }
41}
42
43#[test]
44fn test() {
45    let num1 = "2".to_string();
46    let num2 = "3".to_string();
47    let res = "6".to_string();
48    assert_eq!(Solution::multiply(num1, num2), res);
49    let num1 = "123".to_string();
50    let num2 = "456".to_string();
51    let res = "56088".to_string();
52    assert_eq!(Solution::multiply(num1, num2), res);
53}
rustgym/leetcode/_43_multiply_strings.rs

rustgym/leetcode/
_43_multiply_strings.rs
