Question

How to write an example of O(n^2) time complexity in C

Answer 1

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
   
#define N 3

// The O(n^2) time complexity = running time of an algorithm 
// grows quadratically with n (the size of the input)

// The total number of print operations = N * N
// N = size of the matrix (N rows and N columns)
// time complexity = square of the input size = O(N^2)

void print_matrix(int matrix[][N]);
   
int main(void)
{
    int matrix[N][N] = { {0}, {0} };
      
    srand(time(NULL));
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            matrix[i][j] = rand() % 100 + 1;
        }
    }
       
    print_matrix(matrix);
       
    return 0;
}
   
void print_matrix(int matrix[][N]) {
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            printf("%5i", matrix[i][j]);
        }
            
        printf("\n");
    }
}
  
  
   
/* 
run:
   
    3   27   78
   99   89    5
   76   50   43
   
*/

 

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