Rust solution to https://leetcode.com/problems/multiply-strings/

multiply_strings.rs

use std::vec::Vec;

impl Solution {
    pub fn multiply(num1: String, num2: String) -> String {
        let one: Vec<u32> = num1.chars().map(|c| c.to_digit(10).unwrap()).rev().collect();
        let other: Vec<u32> = num2.chars().map(|c| c.to_digit(10).unwrap()).rev().collect();
        
        let mut tmp: Vec<u32> = vec![0; one.len() + other.len() + 1];
        
        for (i, el1) in one.iter().enumerate() {
            for (j, el2) in other.iter().enumerate() {
                tmp[i + j] += el1 * el2;
            }
        }
        
        let mut carry = 0;
        let l = tmp.len();
        for i in 0..(l - 1) {
            let curr = tmp[i] + carry;
            tmp[i] = curr % 10;
            carry = curr / 10;
        }
        tmp[l - 1] = carry;
        let ret = tmp.into_iter().rev().skip_while(|&x| x == 0).map(|c| c.to_string()).collect::<String>();
        if ret.is_empty() {
            return "0".to_string();
        }
        ret
    }
}