Added task 2011

src/main/java/g2001_2100/s2011_final_value_of_variable_after_performing_operations/Solution.java

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+package g2001_2100.s2011_final_value_of_variable_after_performing_operations;
+
+// #Easy #Array #String #Simulation #2021_10_26_Time_2_ms_(36.12%)_Space_40.1_MB_(100%)
+
+public class Solution {
+ public int finalValueAfterOperations(String[] operations) {
+ int c1 = 0, c2 = 0;
+ for (int i = 0; i < operations.length; i++) {
+ if (operations[i].equals("--X") || operations[i].equals("X--")) ++c1;
+ else ++c2;
+ }
+ return c2 - c1;
+ }
+}

src/main/java/g2001_2100/s2011_final_value_of_variable_after_performing_operations/readme.md

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+2011\. Final Value of Variable After Performing Operations
+
+Easy
+
+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--"`.

src/test/java/g2001_2100/s2011_final_value_of_variable_after_performing_operations/SolutionTest.java

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+package g2001_2100.s2011_final_value_of_variable_after_performing_operations;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+import org.junit.jupiter.api.Test;
+
+class SolutionTest {
+ @Test
+ void finalValueAfterOperations() {
+ assertThat(
+ new Solution().finalValueAfterOperations(new String[] {"--X", "X++", "X++"}),
+ equalTo(1));
+ }
+
+ @Test
+ void finalValueAfterOperations2() {
+ assertThat(
+ new Solution().finalValueAfterOperations(new String[] {"++X", "++X", "X++"}),
+ equalTo(3));
+ }
+
+ @Test
+ void finalValueAfterOperations3() {
+ assertThat(
+ new Solution().finalValueAfterOperations(new String[] {"X++", "++X", "--X", "X--"}),
+ equalTo(0));
+ }
+}