#include <stdio.h>
int main(void) {
    printf("Initial heap: free[0-9] used[10-19] free[20-29]\n");
    printf("Free list: addr=0 len=10 -> addr=20 len=10\n");
    printf("Allocate 1 byte from second free chunk:\n");
    printf("Returned pointer: 20\n");
    printf("Updated free list: addr=0 len=10 -> addr=21 len=9\n");
    printf("Free the middle used block (addr=10):\n");
    printf("Without coalescing: addr=10 len=10 -> addr=0 len=10 -> addr=21 len=9\n");
    printf("With coalescing: addr=0 len=30\n");
    return 0;
}