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https://brunch.co.kr/magazine/highschool

나는 고졸사원이다 매거진

솔직한 브런치라 좋다.

class Solution {

    public int solution(int[] A) {

        // write your code in Java SE 8

        int sum=0;       

        Arrays.sort(A);       

       

        for(int i=0; i < A.length ; i++) {

            if(A[i+1] - A[i] != 1) return A[i]+1;

        }

        return 0;

    }

}

 

class Solution { public int solution(int[] A) { // write your code in Java SE 8 int sum=0; for(int i=0; i < A.length ; i++) sum ^= A[i] ^ (i+1); return sum ^(A.length+1); } }

 

 

Task description

A zero-indexed array A consisting of N different integers is given. The array contains integers in the range [1..(N + 1)], which means that exactly one element is missing.

 

Your goal is to find that missing element.

 

Write a function:

 

class Solution { public int solution(int[] A); }

that, given a zero-indexed array A, returns the value of the missing element.

 

For example, given array A such that:

 

  A[0] = 2

  A[1] = 3

  A[2] = 1

  A[3] = 5

the function should return 4, as it is the missing element.

 

Assume that:

 

N is an integer within the range [0..100,000];

the elements of A are all distinct;

each element of array A is an integer within the range [1..(N + 1)].

Complexity:

 

expected worst-case time complexity is O(N);

expected worst-case space complexity is O(1), beyond input storage (not counting the storage required for input arguments).

Elements of input arrays can be modified.

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