leetcode-java-268. Missing Number

public class Solution {
public int missingNumber(int[] nums) {
int len = nums.length,
result = 0,
i = 0;

Arrays.sort(nums);

for(;i < len;i++) {
if(nums[i] != i) {
result = i;
break;
}
}

return i;
}
}

public class Solution {
public int missingNumber(int[] nums) {
int len = nums.length,
total = 0,
sum = 0,
i = 1;

for(;i <= len;i++) {
total += i;
sum += nums[i - 1];
}

return total - sum;
}
}