[LintCode] Find the Missing Number

public int findMissing(int[] nums) {
        // write your code here
        if(nums.length == 0 || nums == null)
            return 0;
        int missing = 0;
        int n = nums.length;
        for(int i = 0; i <= n; i++) {
            missing^=i;
        } // xor [0,n]
        for(int i : nums)
            missi raneng ^= i;//xor i, i in nums
        return missing;
    }