#include <cs50.h>
#include <stdio.h>
#include <string.h>
// Max number of candidates
#define MAX 9
// preferences[i][j] is number of voters who prefer i over j
int preferences[MAX][MAX];
// locked[i][j] means i is locked in over j
bool locked[MAX][MAX];
// Each pair has a winner, loser
typedef struct
{
int winner;
int loser;
}
pair;
// Array of candidates
string candidates[MAX];
pair pairs[MAX * (MAX - 1) / 2];
int pair_count;
int candidate_count;
// Function prototypes
bool vote(int rank, string name, int ranks[]);
void record_preferences(int ranks[]);
void add_pairs(void);
void sort_pairs(void);
void lock_pairs(void);
void print_winner(void);
int main(int argc, string argv[])
{
// Check for invalid usage
if (argc < 2)
{
printf("Usage: tideman [candidate ...]\n");
return 1;
}
// Populate array of candidates
candidate_count = argc - 1;
if (candidate_count > MAX)
{
printf("Maximum number of candidates is %i\n", MAX);
return 2;
}
for (int i = 0; i < candidate_count; i++)
{
candidates[i] = argv[i + 1];
}
// Clear graph of locked in pairs
for (int i = 0; i < candidate_count; i++)
{
for (int j = 0; j < candidate_count; j++)
{
locked[i][j] = false;
}
}
pair_count = 0;
int voter_count = get_int("Number of voters: ");
// Query for votes
for (int i = 0; i < voter_count; i++)
{
// ranks[i] is voter's ith preference
int ranks[candidate_count];
// Query for each rank
for (int j = 0; j < candidate_count; j++)
{
string name = get_string("Rank %i: ", j + 1);
if (!vote(j, name, ranks))
{
printf("Invalid vote.\n");
return 3;
}
}
record_preferences(ranks);
printf("\n");
}
add_pairs();
sort_pairs();
lock_pairs();
print_winner();
return 0;
}
// Update ranks given a new vote
bool vote(int rank, string name, int ranks[])
{
//- look for a candidate called name
//- if candidate found, update ranks and return true. ranks[i] is the voter's ith preference.
//- if no candidate found, dont update any ranks and return false.
// TODO
for(int i = 0; i < candidate_count; i++){
if(strcmp(candidates[i], name) == 0){
ranks[i] = rank;
return true;
}
}
return false;
}
// Update preferences given one voter's ranks
void record_preferences(int ranks[])
{
//- update the preferences array based on the current voter's rank
// TODO
for(int i = 0; i < candidate_count; i++){
for(int j = 0; j < candidate_count; j++){
if(ranks[i] < ranks[j]) preferences[i][j] += 1;
}
}
for(int i = 0; i < candidate_count; i++){
for(int j = 0; j < candidate_count; j++){
printf("%i\t", preferences[i][j]);
}
printf("\n");
}
return;
}
// Record pairs of candidates where one is preferred over the other
void add_pairs(void)
{
// - add each pair of candidates to pairs array if one candidate is preferred over the other.
// - udpate global variable pair_count to be the total number of pairs
for(int i = 0; i < candidate_count; i++){
for(int j = 0; j < candidate_count; j++){
if(preferences[i][j] > preferences[j][i]){
pairs[pair_count].winner = i;
pairs[pair_count].loser = j;
pair_count += 1;
}
/*else if(preferences[i][j] < preferences[j][i]){
pairs[pair_count].winner = i;
pairs[pair_count].loser = j;
pair_count += 1;
}*/
}
}
//before sort
for(int i = 0; i < pair_count; i++){
printf("pairs %ith is winner %i and loser %i\n", i, pairs[i].winner, pairs[i].loser);
}
printf("\n");
// TODO
return;
}
// Sort pairs in decreasing order by strength of victory
void sort_pairs(void)
{
// TODO
//bubble sort
//backwards, placing the highest value first
for(int i = 0; i < pair_count - 1; i++){
int ifirstDiff = preferences[pairs[i].winner][pairs[i].loser];
int isecondDiff = preferences[pairs[i].loser][pairs[i].winner];
int iComp = ifirstDiff - isecondDiff;
for(int j = i + 1; j < pair_count; j++){
int jfirstDiff = preferences[pairs[j].winner][pairs[j].loser];
int jsecondDiff = preferences[pairs[j].loser][pairs[j].winner];
int jComp = jfirstDiff - jsecondDiff;
if(iComp < jComp){
pair temp = pairs[j];
pairs[j] = pairs[i];
pairs[i] = temp;
}
}
}
for(int i = 0; i < pair_count; i++){
printf("pairs %ith is winner %i and loser %i\n", i, pairs[i].winner, pairs[i].loser);
}
return;
}
// Lock pairs into the candidate graph in order, without creating cycles
void lock_pairs(void)
{
//- update locked to create the locked graph by adding all edges
//in decreasing order of vicotry strength, as long as there is no cycle
// TODO
locked[pairs[0].winner][pairs[0].loser] = true;
for(int i = 1; i < pair_count; i++){
int a = pairs[i].winner;
int b = pairs[i].loser;
for(int j = i + 1; j < pair_count; j++){
int z = pairs[j].winner;
if(a > z) locked[a][b] = true;
else break;
}
}
for(int i = 0; i < candidate_count; i++){
for(int j = 0; j < candidate_count; j++){
printf("%s\t", locked[i][j] ? "true" : "false");
}
printf("\n");
}
return;
}
// Print the winner of the election
void print_winner(void)
{
//-print out the winner of the election, who will be the source of the graph
//- you may assume there may be no more than one source.
int count = 0;
int winner = 0;
for(int i = 0; i < pair_count; i++){
int temp = 0;
for(int j = 0; j < pair_count; j++){
if(locked[i][j]) {
temp ++;
if(count < temp){
count = temp;
winner = i;
} else if (count == temp){
winner = i;
}
}
}
}
printf("%s\n", candidates[winner]);
// TODO
return;
}
/*bool lockrecursive(int winner, int loser){
bool check = true;
if(winner < 0){
winner = 0;
return true;
}
if(loser < 0){
loser = 0;
return true;
}
for(int i = 0; i < winner; i++){
if(locked[winner][i]) check = false;
}
}*/
