杨辉三角的变形（数学）

题目

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
//		1
//		1 1 1
//		1 2 3 2 1
//		1 3 6 7 6 3 1
//		1 4 10 16 19 16 10 4 1
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int[][] res = new int[n+1][2*n];
		for(int i=1;i<=n;i++) {
			res[i][1] = 1;
			res[i][2*i-1] = 1;
		}

		
		//第二列
		for(int i=2;i<=n;i++) {
			res[i][2] = res[i-1][1]+res[i-1][2];
		}
		//大于等于第三列
		for(int i=3;i<=n;i++) {
			for(int j=3;j<=(2*n-1);j++) {
				res[i][j] = res[i-1][j-2]+res[i-1][j-1]+res[i-1][j];
			}
		}
		
		for(int j=1;j<=(2*n-1);j++) {
			if(res[n][j]%2 == 0) {
				System.out.println(j);
				return ;
			}
		}
		System.out.println(-1);
		sc.close();
	}
}

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
//      1
//      1 1 1
//      1 2 3 2 1
//      1 3 6 7 6 3 1
//      1 4 10 16 19 16 10 4 1
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[][] res = new int[n][2 * (n - 1) + 1];
        res[0][0] = 1;
        for (int i = 1; i < n; i++) {
            res[i][0] = 1;
            res[i][2 * i] = 1;
        }
        //第二列
        for (int i = 1; i < n; i++) {
            res[i][1] = res[i - 1][0] + res[i - 1][1];
        }
        //大于等于第三列
        for (int i = 2; i < n; i++) {
            for (int j = 2; j < 2 * (n - 1) + 1; j++) {
                res[i][j] = res[i - 1][j - 2] + res[i - 1][j - 1] + res[i - 1][j];
            }
        }
        for (int j = 0; j < 2 * (n - 1) + 1; j++) {
            if (res[n - 1][j] % 2 == 0) {
                System.out.println(j + 1);
                return ;
            }
        }
        System.out.println(-1);
//      for(int i=0;i
//          for(int j=0;j<(2*(n-1)+1);j++){
//              System.out.print(res[i][j]);
//          }
//          System.out.println();
//      }
        sc.close();
    }
}

下标为0或者1都不能通过全部样例

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
            int num = in.nextInt();
            if(num == 1 || num == 2){
                System.out.println(-1);
            }
            else if(num % 4 == 1 || num % 4 == 3){
                System.out.println(2);
            }
            else if(num % 4 == 0){
                System.out.println(3);
            }
            else if(num % 4 == 2){
                System.out.println(4);
            }
    }
}