Solve #238

Author: aylei

src/lib.rs

@@ -200,3 +200,5 @@ mod n0229_majority_element_ii;
 mod n0230_kth_smallest_element_in_a_bst;
 mod n0231_power_of_two;
 mod n0232_implement_queue_using_stacks;
+mod n0233_number_of_digit_one;
+mod n0238_product_of_array_except_self;

src/n0233_number_of_digit_one.rs

@@ -0,0 +1,33 @@
+/**
+ * [233] Number of Digit One
+ *
+ * Given an integer n, count the total number of digit 1 appearing in all non-negative integers less than or equal to n.
+ *
+ * Example:
+ *
+ *
+ * Input: 13
+ * Output: 6
+ * Explanation: Digit 1 occurred in the following numbers: 1, 10, 11, 12, 13.
+ *
+ *
+ */
+pub struct Solution {}
+
+// submission codes start here
+
+impl Solution {
+    pub fn count_digit_one(n: i32) -> i32 {
+        0
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_233() {}
+}

src/n0238_product_of_array_except_self.rs

@@ -0,0 +1,57 @@
+/**
+ * [238] Product of Array Except Self
+ *
+ * Given an array nums of n integers where n > 1,  return an array output such that output[i] is equal to the product of all the elements of nums except nums[i].
+ *
+ * Example:
+ *
+ *
+ * Input:  [1,2,3,4]
+ * Output: [24,12,8,6]
+ *
+ *
+ * Note: Please solve it without division and in O(n).
+ *
+ * Follow up:<br />
+ * Could you solve it with constant space complexity? (The output array does not count as extra space for the purpose of space complexity analysis.)
+ *
+ */
+pub struct Solution {}
+
+// submission codes start here
+
+/*
+x 2 3 4 = 24
+1 x 3 4 = 12
+1 2 x 4 = 8
+1 2 3 x = 6
+ */
+impl Solution {
+    pub fn product_except_self(nums: Vec<i32>) -> Vec<i32> {
+        if nums.len() < 2 { return vec![] }
+        let mut res = vec![1; nums.len()];
+        let mut n = 1;
+        for i in (0..nums.len()-1).rev() {
+            n *= nums[i+1];
+            res[i] = n;
+        }
+        n = 1;
+        for i in 1..nums.len() {
+            n *= nums[i-1];
+            res[i] *= n;
+        }
+        res
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_238() {
+        assert_eq!(Solution::product_except_self(vec![1,2,3,4]), vec![24,12,8,6]);
+    }
+}