2011. Final Value of Variable After Performing Operations: AC

Author: tan-wei

src/solution/mod.rs

@@ -1515,3 +1515,4 @@ mod s2006_count_number_of_pairs_with_absolute_difference_k;
 mod s2007_find_original_array_from_doubled_array;
 mod s2008_maximum_earnings_from_taxi;
 mod s2009_minimum_number_of_operations_to_make_array_continuous;
+mod s2011_final_value_of_variable_after_performing_operations;

src/solution/s2011_final_value_of_variable_after_performing_operations.rs

@@ -0,0 +1,98 @@
+/**
+ * [2011] Final Value of Variable After Performing Operations
+ *
+ * There is a programming language with only four operations and one variable X:
+ *
+ * 	++X and X++ increments the value of the variable X by 1.
+ * 	--X and X-- decrements the value of the variable X by 1.
+ *
+ * Initially, the value of X is 0.
+ * Given an array of strings operations containing a list of operations, return the final value of X after performing all the operations.
+ *  
+ * Example 1:
+ *
+ * Input: operations = ["--X","X++","X++"]
+ * Output: 1
+ * Explanation: The operations are performed as follows:
+ * Initially, X = 0.
+ * --X: X is decremented by 1, X =  0 - 1 = -1.
+ * X++: X is incremented by 1, X = -1 + 1 =  0.
+ * X++: X is incremented by 1, X =  0 + 1 =  1.
+ *
+ * Example 2:
+ *
+ * Input: operations = ["++X","++X","X++"]
+ * Output: 3
+ * Explanation: The operations are performed as follows:
+ * Initially, X = 0.
+ * ++X: X is incremented by 1, X = 0 + 1 = 1.
+ * ++X: X is incremented by 1, X = 1 + 1 = 2.
+ * X++: X is incremented by 1, X = 2 + 1 = 3.
+ *
+ * Example 3:
+ *
+ * Input: operations = ["X++","++X","--X","X--"]
+ * Output: 0
+ * Explanation: The operations are performed as follows:
+ * Initially, X = 0.
+ * X++: X is incremented by 1, X = 0 + 1 = 1.
+ * ++X: X is incremented by 1, X = 1 + 1 = 2.
+ * --X: X is decremented by 1, X = 2 - 1 = 1.
+ * X--: X is decremented by 1, X = 1 - 1 = 0.
+ *
+ *  
+ * Constraints:
+ *
+ * 	1 <= operations.length <= 100
+ * 	operations[i] will be either "++X", "X++", "--X", or "X--".
+ *
+ */
+pub struct Solution {}
+
+// problem: https://leetcode.com/problems/final-value-of-variable-after-performing-operations/
+// discuss: https://leetcode.com/problems/final-value-of-variable-after-performing-operations/discuss/?currentPage=1&orderBy=most_votes&query=
+
+// submission codes start here
+
+impl Solution {
+    pub fn final_value_after_operations(operations: Vec<String>) -> i32 {
+        operations
+            .iter()
+            .map(|s| if s.contains("++") { 1 } else { -1 })
+            .sum::<i32>()
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_2011_example_1() {
+        let operations = vec_string!["--X", "X++", "X++"];
+
+        let result = 1;
+
+        assert_eq!(Solution::final_value_after_operations(operations), result);
+    }
+
+    #[test]
+    fn test_2011_example_2() {
+        let operations = vec_string!["++X", "++X", "X++"];
+
+        let result = 3;
+
+        assert_eq!(Solution::final_value_after_operations(operations), result);
+    }
+
+    #[test]
+    fn test_2011_example_3() {
+        let operations = vec_string!["X++", "++X", "--X", "X--"];
+
+        let result = 0;
+
+        assert_eq!(Solution::final_value_after_operations(operations), result);
+    }
+}