add rust leetcode

leetcode/src/main/scala/io/github/dreamylost/LeetCode1281.scala

+package io.github.dreamylost
+
+/**
+ *
+ * @author liguobin@growingio.com
+ * @version 1.0,2020/3/12
+ */
+object LeetCode1281 extends App {
+  def subtractProductAndSum(n: Int): Int = {
+    val f = n.toString.toCharArray.map(c => Integer.parseInt(c + ""))
+    f.product - f.sum
+  }
+
+  Console println subtractProductAndSum(234)
+}

rust-leetcode/src/Solution.rs

+use std::borrow::BorrowMut;
 use std::collections::VecDeque;
 use std::ops::Index;
 
@@ -7,10 +8,32 @@ pub fn solutions() {
     leetcode_1365();
     leetcode_1342();
     leetcode_1313();
+    leetcode_1281();
 }
 
 struct Solution;
 
+///整数的各位积和之差
+fn leetcode_1281() {
+    println!("leetcode_1281");
+    impl Solution {
+        pub fn subtract_product_and_sum(n: i32) -> i32 {
+            let mut num = n;
+            let mut muti = 1;
+            let mut sum = 0;
+            while num != 0 {
+                let mut tmp = num % 10;
+                muti *= tmp;
+                sum += tmp;
+                num /= 10;
+            }
+            muti - sum
+        }
+    }
+
+    println!("{}", Solution::subtract_product_and_sum(234));
+}
+
 ///左旋转字符串
 fn interview_58_2() {
     println!("interview_58_2");