ACM. Hj35 serpentine matrix ●

HJ35 Snake matrix ●

describe

The snake matrix is made up of 1 The first natural numbers are arranged in sequence Triangle on matrix .

for example , When the input 5 when , The triangle that should be output is ：

1 3 6 10 15
2 5 9 14
4 8 13
7 12
11

Input description ：

Enter a positive integer N（N No more than 100）

Output description ：

Output one N Snake matrix of row .

Example

Input ：
4
Output ：
1 3 6 10
2 5 9
4 8
7

Answer key

1. mathematics

According to the laws of Mathematics , Line by line calculation and output .

#include <iostream>
#include <vector>
using namespace std;

int main(){
    
    int n;
    cin >> n;
    int matrix[n][n];
    for(int i = 0; i < n; ++i){
    
        int num = i+2;
        matrix[i][0] = (i+1)*i/2 + 1;		//  First column 
        cout << matrix[i][0] << " ";
        for(int j = 1; j < n-i; ++j){
    		//  A line 
            matrix[i][j] = matrix[i][j-1] + num;
            ++num;							//  Addition number 
            cout << matrix[i][j] << " ";
        }
        cout << endl;
    }
    return 0;
}

2. simulation

The method of generating simulated serpentine matrix .

#include <iostream>
#include <vector>
using namespace std;

int main(){
    
    int n;
    cin >> n;
    int matrix[n][n];
    int num = 1;
    for(int i = 1; i <= n; ++i){
    			//  Serpentine matrix generation 
        int row = i - 1;
        int col = 0;
        for(int j = 1; j <= i; ++j){
    
            matrix[row--][col++] = num++;
        }
    }
    for(int i = 0; i < n; ++i){
    				//  Output 
        for(int j = 0; j < n-i; ++j){
    
            cout << matrix[i][j] << " ";
        }
        cout << endl;
    }
    
    return 0;
}