java对角差分

Question

我是编程初学者，在编写对角线差分代码时，我想出了这种方法

 public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    int n = in.nextInt();
    int j = 0;
    int a[][] = new int[n][n];
    int count1 = 0; int count2 = 0;
    int result = 0;
    for(int a_i=0; a_i < n; a_i++){
        for(int a_j = 0;a_j < n;a_j++){
       
            a[a_i][j] = in.nextInt();
        
    }}
    for(int i = 0;i<n;i++)
    {
        count1+=a[i][j];
        System.out.println(count1);
        j++;
    }
    j = 0;
    for(int i = n-1;i>=0;i--)
    {
        count2+=a[i][j];
        System.out.println(count2);
        j++;
    }
    result = Math.abs(count1 - count2);
    System.out.println(result);
}

输入
3
11.2.4
4.5.6
10.8-12
预期产出15
我的输出16

Answer 1

public static int diagonalDifference(List<List<Integer>> arr) {
    
    ListIterator<List<Integer>> itr = arr.listIterator();
    int i = 0,k=arr.size();
    int sumdia1=0 , sumdia2=0;
    List <Integer> inner;
    System.out.println(" k ::: "+k);
    while(itr.hasNext()) {
             inner = itr.next();
             k--;
            sumdia1= sumdia1 + inner.get(i);
            sumdia2= sumdia2+ inner.get(k);
            i++;
        
    }

Answer 2

为什么要做这么多工作？ 你需要一个非常简单的代码：

for(int i = 0;i<n;i++){
    count1+=a[i][i];
    count2+=a[i][n-1-i];
}

Answer 3

在java中，解决方案是

    int result = 0;
    for(int i = 0;i<n;i++){
        l+=a[i][i];
        r+=a[i][n-1-i];
    }
    result = abs(l-r);

对于那些想在python中实现同样功能的人来说，下面是一些方法：

def diagonalDifference(a):
    l = sum(a[i][i] for i in range(len(a)))
    r = sum(a[i][len(a)-1-i] for i in range(len(a)))
    return (abs(r- l))

Answer 4

根据弗兰克的回答，你实际上不需要数组：

for(int i=0; i < n; i++){
  for(int j = 0; j < n; j++){
    int v = in.nextInt();
    count1 += (i == j) ? v : 0;
    count2 += (i + j == n-1) ? v : 0;
  }
}

Answer 5

这里是Javascript。为了可读性，我使用forEach。在Java中也可以做类似的事情

function diagonalDifference(arr) {
    let length = arr.length-1;
    let leftDiag = 0;
    let rightDiag = 0;


    arr.forEach((item, outerIndex) => {
        item.forEach((innerItem, innerIndex) => {
            if (outerIndex === innerIndex) {
                leftDiag = leftDiag + innerItem;
            }
            if (length - outerIndex === innerIndex) {
                rightDiag = rightDiag + innerItem;
            }
        });
    });

    return Math.abs(leftDiag - rightDiag);

}

Answer 6

我用Java解决对角差分问题

public static int diagonalDifference(List<List<Integer>> arr) {
    int primaryDiagnal = 0;
    int secDiagnal = 0;
    int diff;

    for(int i= 0; i<arr.get(0).size(); i++){
        primaryDiagnal += arr.get(i).get(i);
    }

    int col = arr.get(0).size() - 1;
    for(int i= 0; i<arr.get(0).size(); i++){
        secDiagnal += arr.get(i).get(col);
        col--;
    }

    diff = primaryDiagnal - secDiagnal;
    return Math.abs(diff);
 }