Week 6 : Assignments - NPTEL >> Introduction to Programming In C - 2025

Week 6 : Assignment 6 - Question 1

Complete the function isSymmetric(int A[][n], int n) that checks if A is a symmetric matrix and returns 1 if symmetric, 0 otherwise.

Solution :

#include<stdio.h>
// Complete this Function to check if a matrix is symmetric.
// A is an n*n Matrix. Return 1 is A is symmetric and 0 otherwise.

int isSymmetric(int A[10][10], int n) {
  int flag=1;
  for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
          if(A[i][j]!=A[j][i]){
              flag=0;
              break;
          }
        }
    }
    return flag;
}

int main() {
    int n;
    scanf("%d", &n);

    int A[10][10];

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            scanf("%d", &A[i][j]);
        }
    }

    printf("%d",isSymmetric(A,n));

    return 0;
}

Week 6 : Assignment 6 - Question 2

Given an n×n binary Matrix A , where each entry is 0 or 1.

A has a unique path of 1's from A[0][0] to A[n-1][n-1].

The path always goes Right (R) or Down (D).

Write a C Program.to print the directions of this path.

Solution :

#include<stdio.h>
int main() 
{
    int n,i,j;
    int A[10][10];
    scanf("%d", &n);
  
    for (i = 0; i < n; i++) 
    {
        for ( j = 0; j < n; j++) 
        {
            scanf("%d", &A[i][j]);
        }
    }
	i=0;
  	j=0;
  	while (i != n-1 || j !=n-1)
    {
      if(j+1 < n && A[i][j+1] == 1)
      {
        printf("R");
        j++;
      }
      else if(i+1 < n && A[i+1][j] == 1)
      {
        printf("D");
        i++;
      }
    }
  
    
    return 0;
}

Week 6 : Assignment 6 - Question 3

Write a C program to count the number of islands in the matrix.

Solution :

#include<stdio.h>

int main() {
    int n;
    scanf("%d", &n);

    int grid[20][20];
    for(int i = 0; i < n; i++)
        for(int j = 0; j < n; j++)
            scanf("%d", &grid[i][j]);

    int count = 0;

    // Complete the code here. 
    // Compute the number of islands, and store them in count.
	
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            if (grid[i][j] == 1) {
                if ((i == 0 || grid[i-1][j] == 0) && (j == 0 || grid[i][j-1] == 0)) {
                    count++;
                }
            }
        }
    }

    printf("%d", count);
    return 0;
}