From 7e9979da7602f9e8e4553c8cafcf6f9e822b3bbc Mon Sep 17 00:00:00 2001 From: "huangge1199@hotmail.com" Date: Fri, 23 Apr 2021 23:37:22 +0800 Subject: [PATCH] =?UTF-8?q?43:=E5=AD=97=E7=AC=A6=E4=B8=B2=E7=9B=B8?= =?UTF-8?q?=E4=B9=98?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../leetcode/editor/cn/MultiplyStrings.java | 100 ++++++++++++++++++ .../leetcode/editor/cn/MultiplyStrings.md | 21 ++++ 2 files changed, 121 insertions(+) create mode 100644 LeetCode/src/main/java/leetcode/editor/cn/MultiplyStrings.java create mode 100644 LeetCode/src/main/java/leetcode/editor/cn/MultiplyStrings.md diff --git a/LeetCode/src/main/java/leetcode/editor/cn/MultiplyStrings.java b/LeetCode/src/main/java/leetcode/editor/cn/MultiplyStrings.java new file mode 100644 index 0000000..64a3af6 --- /dev/null +++ b/LeetCode/src/main/java/leetcode/editor/cn/MultiplyStrings.java @@ -0,0 +1,100 @@ +//给定两个以字符串形式表示的非负整数 num1 和 num2，返回 num1 和 num2 的乘积，它们的乘积也表示为字符串形式。 +// +// 示例 1: +// +// 输入: num1 = "2", num2 = "3" +//输出: "6" +// +// 示例 2: +// +// 输入: num1 = "123", num2 = "456" +//输出: "56088" +// +// 说明： +// +// +// num1 和 num2 的长度小于110。 +// num1 和 num2 只包含数字 0-9。 +// num1 和 num2 均不以零开头，除非是数字 0 本身。 +// 不能使用任何标准库的大数类型（比如 BigInteger）或直接将输入转换为整数来处理。 +// +// Related Topics 数学 字符串 +// 👍 625 👎 0 + +package leetcode.editor.cn; + +//43:字符串相乘 +public class MultiplyStrings { + public static void main(String[] args) { + //测试代码 + Solution solution = new MultiplyStrings().new Solution(); + //6 + System.out.println(solution.multiply("2", "3")); + //56088 + System.out.println(solution.multiply("123", "456")); + //81 + System.out.println(solution.multiply("9", "9")); + //891 + System.out.println(solution.multiply("9", "99")); + //0 + System.out.println(solution.multiply("9133", "0")); + } + + //力扣代码 + //leetcode submit region begin(Prohibit modification and deletion) + class Solution { + public String multiply(String num1, String num2) { + if ("0".equals(num1) || "0".equals(num2)) { + return "0"; + } + if (num1.length() < num2.length()) { + String temp = num1; + num1 = num2; + num2 = temp; + } + int l1 = num1.length(); + int l2 = num2.length(); + int length = l1 + l2 - 1; + int sum = 0, n1, n2; + StringBuilder str = new StringBuilder(); + for (int i = 1; i <= length; i++) { + for (int j = Math.min(i, l1); j >= (i <= l1 ? 1 : i - l1 + 1) && i + 1 - j <= l2; j--) { + n1 = num1.charAt(l1 - j) - '0'; + n2 = num2.charAt(l2 - i - 1 + j) - '0'; + sum += n1 * n2; + } + str.insert(0, sum % 10); + sum = sum / 10; + } + if (sum > 0) { + str.insert(0, sum); + } + return str.toString(); + +// if (num1.equals("0") || num2.equals("0")) { +// return "0"; +// } +// int[] res = new int[num1.length() + num2.length()]; +// for (int i = num1.length() - 1; i >= 0; i--) { +// int n1 = num1.charAt(i) - '0'; +// for (int j = num2.length() - 1; j >= 0; j--) { +// int n2 = num2.charAt(j) - '0'; +// int sum = (res[i + j + 1] + n1 * n2); +// res[i + j + 1] = sum % 10; +// res[i + j] += sum / 10; +// } +// } +// +// StringBuilder result = new StringBuilder(); +// for (int i = 0; i < res.length; i++) { +// if (i == 0 && res[i] == 0) { +// continue; +// } +// result.append(res[i]); +// } +// return result.toString(); + } + } +//leetcode submit region end(Prohibit modification and deletion) + +} \ No newline at end of file diff --git a/LeetCode/src/main/java/leetcode/editor/cn/MultiplyStrings.md b/LeetCode/src/main/java/leetcode/editor/cn/MultiplyStrings.md new file mode 100644 index 0000000..0e91d83 --- /dev/null +++ b/LeetCode/src/main/java/leetcode/editor/cn/MultiplyStrings.md @@ -0,0 +1,21 @@ +

给定两个以字符串形式表示的非负整数 num1 和 num2，返回 num1 和 num2 的乘积，它们的乘积也表示为字符串形式。

+ +

示例 1:

+ +
输入: num1 = "2", num2 = "3"
+输出: "6"
+ +

示例 2:

+ +
输入: num1 = "123", num2 = "456"
+输出: "56088"
+ +

说明：

+ +
    +
  1. num1 和 num2 的长度小于110。
    2. +
  2. num1 和 num2 只包含数字 0-9。
    3. +
  3. num1 和 num2 均不以零开头，除非是数字 0 本身。
    4. +
  4. 不能使用任何标准库的大数类型（比如 BigInteger）或直接将输入转换为整数来处理。
    5. +
+
Related Topics
  • 数学
  • 字符串
    • \n
  • 👍 625
  • 👎 0
    • \ No newline at end of file