题解 | #最长上升子序列(一)#

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        while (in.hasNextInt()) { // 注意 while 处理多个 case
            int n = in.nextInt();
            int[] arr = new int[n];
            for (int i = 0; i < n; i++) {
                arr[i] = in.nextInt();
            }
            System.out.println(process(arr));
        }
    }
    
    public static int process(int[] arr) {
        if (arr == null || arr.length < 1) {
            return 0;
        }
        int n = arr.length;
        int[] dp = new int[n];
        dp[0] = 1;
        int max = 0;
        for (int i = 1; i < n; i++) {
            dp[i] = 1;
            for (int j = 0; j < i; j++) {
                if (arr[i] > arr[j]) {
                    dp[i] = Math.max(dp[i], dp[j] + 1);
                }
            }
            max = Math.max(max, dp[i]);
        }
        return max;
    }
}