1780. Check if Number is a Sum of Powers of Three: AC

Author: tan-wei

src/solution/mod.rs

@@ -1341,3 +1341,4 @@ mod s1774_closest_dessert_cost;
 mod s1775_equal_sum_arrays_with_minimum_number_of_operations;
 mod s1776_car_fleet_ii;
 mod s1779_find_nearest_point_that_has_the_same_x_or_y_coordinate;
+mod s1780_check_if_number_is_a_sum_of_powers_of_three;

src/solution/s1780_check_if_number_is_a_sum_of_powers_of_three.rs

@@ -0,0 +1,84 @@
+/**
+ * [1780] Check if Number is a Sum of Powers of Three
+ *
+ * Given an integer n, return true if it is possible to represent n as the sum of distinct powers of three. Otherwise, return false.
+ * An integer y is a power of three if there exists an integer x such that y == 3^x.
+ *  
+ * Example 1:
+ *
+ * Input: n = 12
+ * Output: true
+ * Explanation: 12 = 3^1 + 3^2
+ *
+ * Example 2:
+ *
+ * Input: n = 91
+ * Output: true
+ * Explanation: 91 = 3^0 + 3^2 + 3^4
+ *
+ * Example 3:
+ *
+ * Input: n = 21
+ * Output: false
+ *
+ *  
+ * Constraints:
+ *
+ * 	1 <= n <= 10^7
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/check-if-number-is-a-sum-of-powers-of-three/
+// discuss: https://leetcode.com/problems/check-if-number-is-a-sum-of-powers-of-three/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    pub fn check_powers_of_three(n: i32) -> bool {
+        let mut temp = n;
+
+        while temp > 0 {
+            if temp % 3 == 2 {
+                return false;
+            }
+            temp /= 3;
+        }
+
+        true
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_1780_example_1() {
+        let n = 12;
+
+        let result = true;
+
+        assert_eq!(Solution::check_powers_of_three(n), result);
+    }
+
+    #[test]
+    fn test_1780_example_2() {
+        let n = 91;
+
+        let result = true;
+
+        assert_eq!(Solution::check_powers_of_three(n), result);
+    }
+
+    #[test]
+    fn test_1780_example_3() {
+        let n = 21;
+
+        let result = false;
+
+        assert_eq!(Solution::check_powers_of_three(n), result);
+    }
+}