Find Second Largest Number

題意：

在未排序的陣列中，找出第二大的數

解題思路：

class Solution{
    public int findSecondLargest(int[] nums) {
        if (nums == null || nums.length < 2) {
            return -1;
        }

        int first = Integer.MIN_VALUE;
        int second = Integer.MIN_VALUE;

        for (int i = 0; i < nums.length; i++) {
            if (nums[i] > first) {
                second = first;
                first = nums[i];
            } else if (nums[i] > second) {
                second = nums[i];
            }
        }

        return second;
    }
}