Cs50 Tideman Solution Apr 2026

"It's not about the edge you're adding," she whispered. "It's about the path that already exists beneath it."

Kai chuckled. "That's not just Tideman, Maya. That's life. Don't create cycles. Always check if the person you're stepping on has a hidden path back to you."

// Returns true if adding edge winner->loser creates a cycle bool creates_cycle(int winner, int loser) { // If the loser can reach the winner through existing locked edges, // then adding winner->loser would complete a cycle. return dfs(loser, winner); } bool dfs(int current, int target) { if (current == target) return true; for (int i = 0; i < candidate_count; i++) { if (locked[current][i] && dfs(i, target)) return true; } return false; }

Her friend, an old sysadmin named Kai, peered over her shoulder. "You're trying to lock every pair in order of strength, right?" Cs50 Tideman Solution

In a directed graph, adding an edge from A → B creates a cycle if and only if B can already reach A.

Maya submitted her solution. And in the real election that followed, Alice became Keeper of the Orchard—not because she was the strongest in every head-to-head match, but because when paradoxes arose, the village had a coder wise enough to know which locks to leave open. Don't just check for a two-step loop. Use depth-first search to see if the loser has any path to the winner in the existing locked graph. If yes, skip the pair. That’s the entire secret of Tideman.

Maya’s heart sank. She had been checking loser → X → winner . But what about loser → X → Y → winner ? "It's not about the edge you're adding," she whispered

Her job was to "lock in" the strongest edges of victory to create a directed graph of the winner—without creating a cycle.

He drew on the whiteboard:

Maya ran check50 . Green smiles across the board. She leaned back. That's life

"You’re not just looking for a loop," Kai said. "You’re looking for a chain . Before you lock a new edge from winner to loser , ask yourself: is there any path from the loser back to the winner using the edges already locked? If yes, this new edge would complete the cycle. Skip it."

"Show me your cycle detection," Kai said.