1979. Find Greatest Common Divisor of Array: AC

Author: tan-wei

src/solution/mod.rs

@@ -1491,3 +1491,4 @@ mod s1974_minimum_time_to_type_word_using_special_typewriter;
 mod s1975_maximum_matrix_sum;
 mod s1976_number_of_ways_to_arrive_at_destination;
 mod s1977_number_of_ways_to_separate_numbers;
+mod s1979_find_greatest_common_divisor_of_array;

src/solution/s1979_find_greatest_common_divisor_of_array.rs

@@ -0,0 +1,100 @@
+/**
+ * [1979] Find Greatest Common Divisor of Array
+ *
+ * Given an integer array nums, return the greatest common divisor of the smallest number and largest number in nums.
+ * The greatest common divisor of two numbers is the largest positive integer that evenly divides both numbers.
+ *  
+ * Example 1:
+ *
+ * Input: nums = [2,5,6,9,10]
+ * Output: 2
+ * Explanation:
+ * The smallest number in nums is 2.
+ * The largest number in nums is 10.
+ * The greatest common divisor of 2 and 10 is 2.
+ *
+ * Example 2:
+ *
+ * Input: nums = [7,5,6,8,3]
+ * Output: 1
+ * Explanation:
+ * The smallest number in nums is 3.
+ * The largest number in nums is 8.
+ * The greatest common divisor of 3 and 8 is 1.
+ *
+ * Example 3:
+ *
+ * Input: nums = [3,3]
+ * Output: 3
+ * Explanation:
+ * The smallest number in nums is 3.
+ * The largest number in nums is 3.
+ * The greatest common divisor of 3 and 3 is 3.
+ *
+ *  
+ * Constraints:
+ *
+ * 	2 <= nums.length <= 1000
+ * 	1 <= nums[i] <= 1000
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/find-greatest-common-divisor-of-array/
+// discuss: https://leetcode.com/problems/find-greatest-common-divisor-of-array/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    pub fn find_gcd(nums: Vec<i32>) -> i32 {
+        let (mn, ma) = nums.iter().fold((1000, 1), |(mn, ma), &y| {
+            if (y > ma) {
+                if (y < mn) {
+                    (y, y)
+                } else {
+                    (mn, y)
+                }
+            } else if (y < mn) {
+                (y, ma)
+            } else {
+                (mn, ma)
+            }
+        });
+
+        (1..=mn).fold(1, |x, y| if (mn % y == 0) && (ma % y) == 0 { y } else { x })
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1979_example_1() {
+        let nums = vec![2, 5, 6, 9, 10];
+
+        let result = 2;
+
+        assert_eq!(Solution::find_gcd(nums), result);
+    }
+
+    #[test]
+    fn test_1979_example_2() {
+        let nums = vec![7, 5, 6, 8, 3];
+
+        let result = 1;
+
+        assert_eq!(Solution::find_gcd(nums), result);
+    }
+
+    #[test]
+    fn test_1979_example_3() {
+        let nums = vec![3, 3];
+
+        let result = 3;
+
+        assert_eq!(Solution::find_gcd(nums), result);
+    }
+}