Now, let’s get back to our two young superheroes again, still inside the barrier created by Sarah. Joshua curiously asked, "What is the plan?”

  Sarah enthusiastically replied, “Remember how Dennis said that Triangular has got the power of data structures?”

  “Yes,” replied Joshua.

  Sarah then continued, "So, I think I've figured out how his powers wor–"

  "BAM!" A sudden sound rang out as Triangular punched the barrier from the outside.

  "Come on out, don't test my patience. You guys don’t want me to get mad," said Triangular in an annoyed tone.

  Sarah said in a serious tone, “Ok, I’ll tell it faster, cause this guy outside is going crazy.”

  Triangular went towards the machine gun Sarah had created and tried to use it to shoot the dome down, but he could not operate it.

  Inside the barrier, Sarah continued to explain the plan. “I think Triangular’s teleported punches are based on the array data structure, where he selects locations just like how, in a computer program, the compiler selects memory locations to store the elements of an array. In these selected locations, he can perform a teleported punch at any random location of his choice, just like how one can randomly access data in an array.”

  Joshua then said, “Ok, that explains his teleported punches, but what about his teleportation powers?"

  Sarah then said, “That is probably based on either a linked list or a tree data structure. He once again selects the locations where he can teleport, but in this situation, he can’t teleport back to a previous location. This is because in both the linked list and the tree data structure, each node can’t point back to the previous node or parent node, respectively.”

  Joshua, still doubtful of Sarah’s hypothesis, asked her, "How did you come to the conclusion that he can't teleport to a previous location where he was?"

  Sarah responded by saying, “Well, if you remember, when we both started to attack him with your fireballs and my machine gun, he initially teleported behind us. But after that, he kept teleporting to locations in front of us and also kept moving back. So, based on that experience, I came up with my conclusion.”

  Joshua, ecstatic with the knowledge gained about Triangular’s powers, said to Sarah, “Now that we have an understanding of Triangular’s powers, I think now we–”

  Before Joshua could finish his sentence, he was interrupted by an explosion on the mini dome barrier. It was caused by a bomb thrown by Triangular, which destroyed the barrier and sent both of the young heroes flying backward. Despite the explosion, neither of them was injured much because they had been protected by the barrier, so they quickly recovered and got to their feet.

  Sarah mockingly said, “Come on, Triangular! I thought you were one of the toughest and baddest supervillains out there, but it took you this much time to destroy the dome barrier I created.”

  Triangular smiled and said, "I thought of destroying your barrier by using the machine gun you created for irony, but I couldn't operate it because it had no trigger. How did you operate it without a trigger?"

  Sarah said with an annoyed look on her face, “I use my powers to move the hammer of the gun in order to shoot the bullets. Anyway, why are you asking these stupid questions?”

  Still smiling, Triangular responded, “I asked you these questions to extend your lives by a few seconds because I won't go easy on you guys anymore. And if I don't go easy on someone in a fight, I end that person's life quickly.”

  Upon hearing those words, Sarah got really angry and said, “Oh yeah, let’s see about that!”

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  She touched the ground and created a large, cuboidal metal block that emerged near her. Remaining firmly attached to the ground, Sarah tried to hit Triangular with it by elongating it towards him. Before the block could reach Triangular to deliver a blow, he dodged it by teleporting to a location behind Sarah and Joshua. Both Sarah and Joshua turned around and found Triangular behind them. Sarah swung her large block towards Triangular to hit him, and Joshua shot his fireballs at him. Once again, Triangular dodged those attacks by teleporting, but this time, he did not reappear in front of them.

  While the heroes were wondering where Triangular went, a bomb was suddenly thrown at them from behind. The heroes realized the presence of the bomb a bit too late. Sarah quickly tried to make a wall between themselves and the bomb for protection, but she could not complete it in time. The bomb exploded upon coming in contact with the incomplete wall, shattering it and causing severe damage to Joshua.

  Sarah protected herself by turning her clothes into metal, forming a suit of armor. Joshua did not lose any body parts or die from the explosion because Sarah's partially completed wall and his Lempika superhero uniform provided some protection, but he suffered enough damage to make him faint.

  The explosion sent Sarah and Joshua flying back in different directions, creating a significant distance between them, but Sarah was mostly unharmed due to her armor. Sarah got to her feet, and upon seeing Joshua, she screamed, “Joshua, are you alright?”

  Receiving no response, with a mixed feeling of sadness and anger, she concluded that he had fainted. She thought to herself, I thought he couldn’t teleport back to a previous position. I was completely wrong.

  After pondering for a couple of seconds, a sudden realization struck Sarah. I completely forgot about doubly linked lists, where each node can also point back to a previous node! That was very stupid of me... Since his powers are based on data structures, he will definitely have a limited number of locations, just like how linked lists and trees have a limited number of nodes. I’ll keep attacking him until he runs out of nodes. I also noticed that he takes a few seconds before he can change his powers, like how he endured some hits from Joshua’s fireballs before switching from his teleporting punches to his actual teleportation, instead of dodging immediately. I just won't give him enough time to change by quickly and continuously attacking him.

  In a fit of rage, Sarah touched the ground with her hands and again started to move the large block she had created to hit Triangular, but he kept teleporting to dodge it. This time, in order to prevent him from returning to a previous location, Sarah created large spikes on the ground that would cause severe cuts to anyone standing on or near them. However, due to the distance between the locations and herself, it took her some time to completely finish forming those spikes.

  That delay allowed Triangular to teleport back to his previous locations once or twice. He teleported right next to Sarah and touched her, but before he could attack or cause any damage, she jumped away. She touched the ground to create a large spike near her and tried to stab Triangular with it, but he dodged it by teleporting.

  Sarah kept trying to hit him with the large metal block while creating spikes on his previous locations, but he kept dodging her attacks. All this effort was draining a lot of Sarah's energy and making her tired, but she kept pushing herself.

  Then, all of a sudden, Triangular stood still in one place. Even though Sarah's metal block was nearing him, he did not teleport.

  He’s out of locations! Sarah thought ecstatically, and she landed a clean hit on the front of his body.

  Triangular went flying backward and was significantly injured, falling face-first to the ground from the impact. Sarah once again brought the large metal block down from the top to crush him, preventing him from getting any breathing space. But this time, when it landed, it didn’t hurt him.

  Triangular slowly got to his feet. Pushing the large metal block away with a single hand, he said, “That won’t work... There is no way out of this one... You’re done. Your death sentence began as soon as you started fighting against me.”

  In a state of shock, Sarah tried to hit him multiple times, but no matter how much force she used with the block, Triangular didn't even move an inch, nor did he get hurt at all.

  Triangular smiled and said, “Give up. It will make it easier for the both of us, as there is no chance of you defeating me.” He then ran towards Sarah, throwing his bombs while moving.

  Sarah created metal pillars from the ground to intercept the bombs before they could reach her, ensuring they exploded harmlessly at a distance. She also tried hitting Triangular with the metal block and stabbing him with thick, sharp spikes she created near him to halt his advance. However, all her attacks were completely ineffective.

  Triangular stopped running and started to walk, steadily closing the gap between himself and Sarah. Sarah realized that if he got any closer, there would be no way to avoid a point-blank blast. She ran away to create some distance but could not run very fast, as she was utterly exhausted.

  Triangular stopped walking, standing still in one position, and did nothing for a few seconds. Then, he used his teleporting punch—but this time, instead of using the attack to strike her, he used it to teleport a live bomb right next to Sarah at close range.

  Coincidentally, just as Triangular teleported the bomb, Sarah had stopped running, and it exploded upon coming in contact with her. The explosion threw her backward, and the damage she took caused her to faint instantly. The armor she had created from her clothes shattered from the blast, but it successfully protected her from death or dismemberment.

  Triangular panted and said, “Wow, I’m exhausted. These brats were quite tough to beat, especially the girl. I never thought I would have to use my Stack power.” He bent down a bit, resting his hands on his knees to catch his breath.

  I had to, he thought to himself, because I wasn't sure if one teleporting bomb could finish her due to her armor. I couldn't risk her learning about my Stack form, as she would have devised a counter. So, I had to exhaust her first to ensure that one bomb explosion would be enough, which forced me to use my Stack power. I really hate using it; it drains a lot from me and it's very risky.

  Triangular stood up straight again. They’re probably dead, but just to make sure, I’ll finish them off using a teleporting slash with the dagger Big Bro gave me, he thought.

  Just before Triangular could finish off the young superheroes with his dagger, a fire blast erupted out of the blue.

  "Big broo!" Triangular screamed in pain as the flames struck him.

  From the air—the source of the fire blast—descended a person whose body appeared to be made entirely of flames. As soon as they landed on the ground, the fire dissipated, revealing their normal form.

  It was none other than Sharank.