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/*
Challenge 009
Challenge #2
Write a script to perform different types of ranking as described below:
1. Standard Ranking (1224): Items that compare equal receive the same ranking
number, and then a gap is left in the ranking numbers.
2. Modified Ranking (1334): It is done by leaving the gaps in the ranking
numbers before the sets of equal-ranking items.
3. Dense Ranking (1223): Items that compare equally receive the same
ranking number, and the next item(s) receive the immediately following
ranking number.
*/
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
typedef struct score_t {
int seq;
int score;
int rank;
} score_t;
void* check_mem(void* p) {
if (!p) {
fputs("Out of memory", stderr);
exit(EXIT_FAILURE);
}
return p;
}
int rev_by_score(const void* a, const void* b) {
return -(((score_t*)a)->score - ((score_t*)b)->score); // reverse-sort
}
int by_seq(const void* a, const void* b) {
return ((score_t*)a)->seq - ((score_t*)b)->seq;
}
void standard_ranking(int num_scores, score_t* scores) {
qsort(scores, num_scores, sizeof(score_t), rev_by_score);
int rank = 1;
for (int i = 0; i < num_scores; i++) {
int count = 0;
for (int j = i; j < num_scores && scores[i].score == scores[j].score; j++) {
count++;
scores[j].rank = rank;
}
rank += count;
i += count - 1;
}
qsort(scores, num_scores, sizeof(score_t), by_seq);
}
void modified_ranking(int num_scores, score_t* scores) {
qsort(scores, num_scores, sizeof(score_t), rev_by_score);
int rank = 1;
for (int i = 0; i < num_scores; i++) {
int count = 0;
for (int j = i; j < num_scores && scores[i].score == scores[j].score; j++)
count++;
rank += count-1;
for (int j = i; j < num_scores && scores[i].score == scores[j].score; j++)
scores[j].rank = rank;
rank++;
i += count - 1;
}
qsort(scores, num_scores, sizeof(score_t), by_seq);
}
void dense_ranking(int num_scores, score_t* scores) {
qsort(scores, num_scores, sizeof(score_t), rev_by_score);
int rank = 1;
for (int i = 0; i < num_scores; i++) {
int count = 0;
for (int j = i; j < num_scores && scores[i].score == scores[j].score; j++) {
count++;
scores[j].rank = rank;
}
rank++;
i += count - 1;
}
qsort(scores, num_scores, sizeof(score_t), by_seq);
}
int main(int argc, char* argv[]) {
if (argc < 2) return EXIT_FAILURE;
int num_scores = argc - 1;
score_t* scores = check_mem(calloc(num_scores, sizeof(score_t)));
for (int i = 0; i < num_scores; i++) {
scores[i].seq = i;
scores[i].score = atoi(argv[i + 1]);
}
printf("Data: ");
for (int i = 0; i < num_scores; i++) {
printf("%d", scores[i].score);
if (i + 1 < num_scores)
printf(", ");
}
printf("\n");
standard_ranking(num_scores, scores);
printf("Standard ranking: ");
for (int i = 0; i < num_scores; i++) {
printf("%d", scores[i].rank);
if (i + 1 < num_scores)
printf(", ");
}
printf("\n");
modified_ranking(num_scores, scores);
printf("Modified ranking: ");
for (int i = 0; i < num_scores; i++) {
printf("%d", scores[i].rank);
if (i + 1 < num_scores)
printf(", ");
}
printf("\n");
dense_ranking(num_scores, scores);
printf("Dense ranking: ");
for (int i = 0; i < num_scores; i++) {
printf("%d", scores[i].rank);
if (i + 1 < num_scores)
printf(", ");
}
printf("\n");
free(scores);
}
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