daily commit 2024-04-24

2024-04-24/README.md

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+# 136. Single Number
+
+Problem Link: https://leetcode.com/problems/single-number/
+
+Easy
+
+Given a non-empty array of integers nums, every element appears twice except for one. Find that single one.
+
+You must implement a solution with a linear runtime complexity and use only constant extra space.
+
+Example 1:
+
+```
+Input: nums = [2,2,1]
+Output: 1
+```
+
+Example 2:
+
+```
+Input: nums = [4,1,2,1,2]
+Output: 4
+```
+
+Example 3:
+
+```
+Input: nums = [1]
+Output: 1
+```
+
+Constraints:
+
+    1 <= nums.length <= 3 * 104
+    -3 * 104 <= nums[i] <= 3 * 104
+    Each element in the array appears twice except for one element which appears only once.

2024-04-24/main.go

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+func singleNumber(nums []int) int {
+    // create hashmap
+    // if value in hashset then pop value
+    // the value that stays in the hashset is the answer
+    m := make(map[int]int)
+
+    for i := 0; i < len(nums); i++ {
+        value := nums[i]
+        _, keyExists := m[value]
+        if keyExists {
+            delete(m, value)
+            continue
+        }
+        m[value] = 1
+    }
+    answer := 0
+    for key, _ := range m {
+        answer = key
+    }
+    return answer
+}