Que09|793. 高精度乘法

题目：793. 高精度乘法 - AcWing题库

思路/想法：

代码实现：

import java.util.*;
public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String s1 = sc.next();
        int b = sc.nextInt();
        
        int[] arr1 = new int[s1.length()];
        int j = 0;
        for (int i = s1.length() - 1; i >= 0; i--) arr1[j++] = s1.charAt(i) - '0';
        
        List<Integer> ans = multiply(arr1, b);
        
        for (int i = ans.size() - 1; i >= 0; i--) {
            System.out.print(ans.get(i));
        }
    }
    public static List<Integer> multiply(int[] arr1, int b) {
        List<Integer> ans = new ArrayList<>();
        int t = 0;
        for (int i = 0; i < arr1.length || t != 0; i++) {
            if (i < arr1.length) t += arr1[i] * b;
            ans.add(t % 10);
            t /= 10;
        }
        while (ans.size() > 1 && ans.get(ans.size() - 1) == 0) ans.remove(ans.size() - 1);
        return ans;
    }
}