打印给定方阵的所有次对角线元素
给定大小为 n * n 的正方形矩阵 mat[][] 。任务是打印位于给定矩阵的次对角线上的所有元素。 例:
输入: mat[][] = { {1，2，3}， {3，3，4，}， {2，4，6}} 输出:3 4 T9】输入: mat[][] = { {1，2，3，4}， {3，3，4，4}， {2，4，6，3}， {1
方法:正方形矩阵的次对角线是位于构成主对角线的元素正下方的元素集。对于主对角线元素，它们的索引类似于(i = j)，对于次对角线元素，它们的索引类似于 i = j + 1 (i 表示行，j 表示列)。 因此元素 arr[1][0]，arr[2][1]，arr[3][2]，arr[4][3]，…。是亚对角线的元素。 要么遍历矩阵的所有元素，只打印 i = j + 1 的那些需要 O(n 2 )时间复杂度的元素，要么只打印从 1 到 row count–1 的遍历行，并将元素打印为 arr[row][row–1]。 以下是上述方法的实施:
C++
// C++ implementation of the approach
#include <bits/stdc++.h>
using namespace std;
#define R 4
#define C 4
// Function to print the sub diagonal
// elements of the given matrix
void printSubDiagonal(int arr[R][C])
{
for (int i = 1; i < R; i++) {
cout << arr[i][i - 1] << " ";
}
}
// Driver code
int main()
{
int arr[R][C] = { { 1, 2, 3, 4 },
{ 5, 6, 7, 8 },
{ 9, 10, 11, 12 },
{ 13, 14, 15, 16 } };
printSubDiagonal(arr);
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java implementation of the approach
import java.io.*;
class GFG
{
static int R = 4;
static int C = 4;
// Function to print the sub diagonal
// elements of the given matrix
static void printSubDiagonal(int arr[][])
{
for (int i = 1; i < R; i++)
{
System.out.print(arr[i][i - 1] + " ");
}
}
// Driver code
public static void main (String[] args)
{
int arr[][] = { { 1, 2, 3, 4 },
{ 5, 6, 7, 8 },
{ 9, 10, 11, 12 },
{ 13, 14, 15, 16 } };
printSubDiagonal(arr);
}
}
// This code is contributed by ajit.
Python 3
# Python3 implementation of the approach
R = 4
C = 4
# Function to print the sub diagonal
# elements of the given matrix
def printSubDiagonal(arr):
for i in range(1, R):
print(arr[i][i - 1], end = " ")
# Driver code
arr = [[ 1, 2, 3, 4 ],
[ 5, 6, 7, 8 ],
[ 9, 10, 11, 12 ],
[ 13, 14, 15, 16 ]]
printSubDiagonal(arr);
# This code is contributed
# by Mohit Kumar
C
// C# implementation of the approach
using System;
class GFG
{
static int R = 4;
static int C = 4;
// Function to print the sub diagonal
// elements of the given matrix
static void printSubDiagonal(int[,] arr)
{
for (int i = 1; i < R; i++)
{
Console.Write(arr[i, i - 1] + " ");
}
}
// Driver code
public static void Main ()
{
int [,]arr = {{ 1, 2, 3, 4 },
{ 5, 6, 7, 8 },
{ 9, 10, 11, 12 },
{ 13, 14, 15, 16 }};
printSubDiagonal(arr);
}
}
// This code is contributed by CodeMech.
java 描述语言
<script>
// Javascript implementation of the approach
var R = 4
var C = 4
// Function to print the sub diagonal
// elements of the given matrix
function printSubDiagonal(arr)
{
for (var i = 1; i < R; i++) {
document.write( arr[i][i - 1] + " ");
}
}
// Driver code
var arr = [ [ 1, 2, 3, 4 ],
[ 5, 6, 7, 8 ],
[ 9, 10, 11, 12 ],
[ 13, 14, 15, 16 ] ];
printSubDiagonal(arr);
</script>
Output:
5 10 15
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