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  1. Prepare
  2. Algorithms
  3. Bit Manipulation
  4. Lonely Integer
  5. Discussions

Lonely Integer

  • RodneyShag
     + 9 comments

    Java solution - passes 100% of test cases

    O(n) runtime. O(1) space. Uses XOR. Keep in mind:

    1. x ^ x = 0
    2. x ^ 0 = x
    3. XOR is commutative and associative
    public static int lonelyInteger(int [] array) {
    int val = 0;
    for (int num : array) {
        val = val ^ num; // ^ is XOR operator
    }
    return val;
}

    From my HackerRank Java solutions.