Example: Find Symmetric Pairs (Brute-Force) in C

// Find Symmetric Pairs (Brute-Force)
#include <stdio.h>

// Structure to represent a pair of integers
struct Pair {
    int first;
    int second;
};

int main() {
    // Step 1: Define the array of pairs
    struct Pair pairs[] = {{1, 2}, {3, 4}, {5, 2}, {2, 1}, {4, 3}, {6, 7}};
    int n = sizeof(pairs) / sizeof(pairs[0]);

    printf("Original Pairs:\n");
    for (int i = 0; i < n; i++) {
        printf("(%d, %d) ", pairs[i].first, pairs[i].second);
    }
    printf("\n\n");

    printf("Symmetric Pairs:\n");
    // Step 2: Iterate through each pair using the outer loop
    for (int i = 0; i < n; i++) {
        // Step 3: Iterate through subsequent pairs using the inner loop
        // Starting j from i + 1 avoids checking a pair with itself and duplicate checks
        for (int j = i + 1; j < n; j++) {
            // Step 4: Check if pairs[j] is the symmetric counterpart of pairs[i]
            if (pairs[i].first == pairs[j].second && pairs[i].second == pairs[j].first) {
                printf("(%d, %d) and (%d, %d)\n", pairs[i].first, pairs[i].second, pairs[j].first, pairs[j].second);
            }
        }
    }

    return 0;
}