268. missing number

Given an array containing n distinct numbers taken from 0, 1, 2, ..., n, find the one that is missing from the array.

Example 1:

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Input: [3,0,1]
Output: 2

Example 2:

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Input: [9,6,4,2,3,5,7,0,1]
Output: 8
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class  {
public int missingNumber(int[] nums) {
if (nums == null || nums.length == 0) return 0;
int sum = 0;
int total = 0;
for (int i = 0; i < nums.length; i++) {
sum += nums[i];
total += i;
}
sum = sum - nums.length;
return total - sum;
}
}