The Three Topics codechef solution in c++

The solution to the Three Topics problem on CodeChef in C++ involves the following steps:

Step 1: Read the input - Use the cin function to read the number of students, N. - Create three arrays: A[], B[], and C[], each of size N, to store the scores of students in three different subjects.

Step 2: Read the scores - Use a for loop to read the scores of students in subject A and store them in the array A[]. - Repeat the same process to read the scores of students in subjects B and C, and store them in arrays B[] and C[] respectively.

Step 3: Calculate the topic scores - Create three more arrays: AB[], BC[], and CA[], each of size N, to store the topic scores for each student. - Use a nested for loop to iterate over each pair of students (i, j) and calculate the topic scores for AB[], BC[], and CA[] using the formula mentioned in the problem statement. - The formula for calculating the topic scores is: AB[i] = A[i] - B[j] BC[i] = B[i] - C[j] CA[i] = C[i] - A[j]

Step 4: Sort the topic scores - Use the sort function to sort the arrays AB[], BC[], and CA[] in non-decreasing order.

Step 5: Count the number of valid triples - Initialize a variable, count, to 0. - Use three pointers, p1, p2, and p3, to iterate over the sorted arrays AB[], BC[], and CA[] respectively. - Use a while loop to iterate until any of the pointers reaches the end of its respective array. - Inside the loop, check if AB[p1] <= BC[p2] and BC[p2] <= CA[p3]. - If the condition is true, increment the count variable by 1 and move the p2 pointer to the next position. - If the condition is false, move the pointer that points to the smallest value to the next position. - Continue this process until all valid triples have been counted.

Step 6: Print the result - After the loop ends, print the value of the count variable, which represents the number of valid triples.

That's it! This solution reads the input, calculates the topic scores, sorts them, counts the number of valid triples, and finally prints the result.