Cs50 Tideman Solution [hot] May 2026

CS50 Tideman problem set is widely considered one of the most difficult in the course because it requires transitioning from simple loops to graph theory

function must correctly sort pairs in decreasing order of "strength of victory" (the number of voters who preferred the winner over the loser) before lock_pairs is called. : The simplest base case for the recursion is when the node of the current edge is the same as the node of the initial edge you are trying to lock. Graph Representation locked[i][j] 2D boolean array represents a directed edge from candidate to candidate Cs50 Tideman Solution

add_pairs(); sort_pairs(); lock_pairs(); print_winner(); return 0;

Why loser → winner in the check? Because we already have edges in direction of winner → loser. If loser can reach winner, adding winner → loser closes the cycle. CS50 Tideman problem set is widely considered one

// If we have reached the winner again, we have a cycle if (loser == winner)

1. Read Input: Read in the number of voters, candidates, and ranked ballots.
2. Initialize Data Structures: Initialize data structures to store the vote counts and candidate preferences.
3. Count First-Place Votes: Count the first-place votes for each candidate.
4. Check for Winner: Check if a candidate has more than half of the first-place votes. If so, declare them the winner.
5. Eliminate Candidate: Eliminate the candidate with the fewest votes.
6. Recount Votes: Recount the votes after eliminating a candidate.
7. Repeat: Repeat steps 4-6 until a winner is declared.

• How Tideman voting works.
• The purpose of each function in the problem.
• The most challenging part: detecting cycles in a locked graph.
• A clean, correct C solution with explanations.

#include <cs50.h>
#include <stdio.h>
#include <string.h>

Compare Alice and Bob: Alice wins (2/3)
Compare Alice and Charlie: Charlie wins (2/3)
Compare Bob and Charlie: Bob wins (2/3)