牛客网ACM编程模式Java模版

数组输入

import java.util.*;

/*
    对于每一组测试数据，第一行输入两个整数 n，k 代表这个序列的长度和要判断的元素
    接下来输入 n 个整数，a[i] 表示序列中第 i 个元素
    举例：
    5 8
    1 2 3 4 5
 */
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        while (sc.hasNext()) {
            int n = sc.nextInt();
            int k = sc.nextInt();
            int[] nums = new int[n];

            for (int i = 0; i < n; i++) {
                nums[i] = sc.nextInt();
            }

            // write code here ...
        }
    }
}

import java.io.*;
import java.util.*;

/**
 * 输入一个 n * m 的图
 * 举例：
 * 4 4
 * 1122
 * 1222
 * 3111
 * 3333
 */
public class Main {
    // 记得抛异常
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String[] params = br.readLine().trim().split(" ");
        int n = Integer.parseInt(params[0]);
        int m = Integer.parseInt(params[1]);
        char[][] grid = new char[n][m];
        for(int i = 0; i < n; i++)
            grid[i] = br.readLine().trim().toCharArray();
    }
}

---

链表输入

import java.util.*;

/*
    输入一串数字，用逗号分隔
    举例：
    1,2,3,4,5
 */
public class Main {
    static class ListNode {
        int val;
        ListNode next;

        ListNode() {
        }

        ListNode(int val) {
            this.val = val;
        }

        ListNode(int val, ListNode next) {
            this.val = val;
            this.next = next;
        }
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        while (sc.hasNext()) {
            String s = sc.next().toString();
            String[] arr = s.split(",");
            int[] ints = new int[arr.length];

            for (int i = 0; i < ints.length; i++) {
                ints[i] = Integer.parseInt(arr[i]);
            }

            ListNode dummyHead = new ListNode(0);
            ListNode cur = dummyHead;

            for (int i = 0; i < ints.length; i++) {
                cur.next = new ListNode(ints[i]);
                cur = cur.next;
            }
            cur.next = null;

            // write code here ...
        }
    }
}

---

树的输入 1

import java.io.*;
import java.util.*;

/*
    第一行两个数 n, root，分别表示二叉树有 n 个节点，第 root 个节点是二叉树的根
    接下来共 n 行，第 i 行三个数 val_i, left_i, right_i
    分别表示第 i 个节点的值 val 是 val_i，左孩子 left 是第 left_i 个节点，右孩子 right 是第 right_i 个节点
    节点 0 表示空
    举例：
    5 1
    5 2 3
    1 0 0
    3 4 5
    4 0 0
    6 0 0
 */
public class Main {
    static class TreeNode {
        int val;
        TreeNode left;
        TreeNode right;

        TreeNode() {
        }

        TreeNode(int val) {
            this.val = val;
        }

        TreeNode(int val, TreeNode left, TreeNode right) {
            this.val = val;
            this.left = left;
            this.right = right;
        }
    }

    public static void main(String[] args) throws Exception {
        // write code here ...
    } 
}

树的输入 2

import java.util.*;

/*
    输入的第一行表示节点的个数 n（2 ≤ n ≤ 1000，节点的编号为 0 到 n - 1）组成
    下面是 n-1 行，每行有两个整数，第一个数表示父节点的编号，第二个数表示子节点的编号
    举例：
    5
    0 1
    0 2
    1 3
    1 4
 */
public class Main {
    static class TreeNode {
        int val;
        TreeNode left;
        TreeNode right;

        TreeNode() {
        }

        TreeNode(int val) {
            this.val = val;
        }

        TreeNode(int val, TreeNode left, TreeNode right) {
            this.val = val;
            this.left = left;
            this.right = right;
        }
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int numberOfNode = sc.nextInt();
        HashMap<Integer, TreeNode> nodeMap = new HashMap<>();
        
        int rootVal = sc.nextInt();
        TreeNode root = new TreeNode(rootVal);
        int firstChildVal = sc.nextInt();
        TreeNode firstChild = new TreeNode(firstChildVal);
        root.left = firstChild;

        nodeMap.put(firstChildVal, firstChild);
        nodeMap.put(rootVal, root);

        for (int i = 0; i < numberOfNode - 2; i++) {
            int parentVal = sc.nextInt();
            int childVal = sc.nextInt();
            TreeNode child = new TreeNode(childVal);
            TreeNode parent = nodeMap.get(parentVal);

            if (parent != null) {
                if (parent.left == null) {
                    parent.left = child;
                } else if (parent.right == null) {
                    parent.right = child;
                }
            } else {
                parent = new TreeNode(parentVal);
                parent.left = child;
            }

            nodeMap.put(parentVal, parent);
            nodeMap.put(childVal, child);
        }

        // write code here ...

        sc.close();
    }
}