爱奇艺2018春招Java工程师编程题题解

字典序最大子序列

package aiqiyi.demo1;
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String str = scanner.next();
        char[] charArray = str.toCharArray();
        int maxPos = 0;
        StringBuffer sb = new StringBuffer();
        while (maxPos < charArray.length) {
            int maxVlue = Integer.MIN_VALUE;
            for (int i = maxPos; i < charArray.length; i++) {
                if (charArray[i] > maxVlue) {
                    maxVlue = charArray[i];
                    maxPos = i;
                }
            }
            sb.append((char) maxVlue);
            maxPos++;
        }
        System.out.println(sb.toString());
    }
}

三个整数

package aiqiyi.demo2;
import java.util.Arrays;
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int[] arr = new int[3];
        for (int i = 0; i < arr.length; i++) {
            arr[i] = scanner.nextInt();
        }
        Arrays.sort(arr);
        if ((arr[2] - arr[1] + arr[2] - arr[0]) % 2 == 0) {
            System.out.println((arr[2] - arr[1] + arr[2] - arr[0]) / 2);
        } else {
            System.out.println((arr[2] - arr[1] + arr[2] - arr[0] + 3) / 2);
        }
    }
}

牛牛配糖果

package aiqiyi.demo3;
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();// 颜色种类
        int m = scanner.nextInt();// 盒子放置m个糖果
        int[] l = new int[n];
        int[] r = new int[n];
        int least = 0;
        int[] rem = new int[n];// 表示每一种颜色剩余可以加的
        for (int i = 0; i < r.length; i++) {
            l[i] = scanner.nextInt();
            r[i] = scanner.nextInt();
            least += l[i];
            rem[i] = r[i] - l[i];
        }
        int target = m - least;
        long[][] dp = new long[n + 1][target + 1];
        for (int i = 0; i < dp.length; i++) {
            dp[i][0] = 1;
        }
        for (int i = 1; i <= n; i++) {
            for (int j = 1; j <= target; j++) {
                for (int k = 0; k <= rem[i - 1]; k++) {
                    if (j - k >= 0)
                        dp[i][j] += dp[i - 1][j - k];
                }
            }
        }
        System.out.println(dp[n][target]);
    }
}