C语言成绩过滤函数问题：无法正确移除指定日期成绩

需求说明 #

• 实现int digits_in_date()函数，接收成绩数组
• 对通过课程（成绩≥6/满分10）累计ECTS学分≥30的学生，移除其成绩中日期所含不同数字数量最少的所有记录
• 通过姓名识别同一学生，数据合法，禁止使用辅助字符串，必须用结构体实现

我编写了对应代码，部分测试用例可得到正确结果，但存在正确性问题（如失败测试用例中未按预期移除Fata Fatic的成绩），且尝试优化时易导致程序崩溃或运行效率低下。以下为我的代码及测试用例：

我的代码 #

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

struct Date {
    int day, month, year;
};

struct Course {
    int id;
    char name[100];
    double ects;
};

struct Grade {
    char fullname[100];
    int grade;
    struct Course course;
    struct Date date;
};

int count_different_digits(int number) {
    int digits[10] = {0};
    while (number > 0) {
        digits[number % 10]++;
        number /= 10;
    }

    int different_digits_count = 0;
    for (int i = 0; i < 10; i++) {
        if (digits[i] > 0) {
            different_digits_count++;
        }
    }

    return different_digits_count;
}

int digits_in_date(struct Grade grades[], int number_of_grades) {
    for (int i = 0; i < number_of_grades; i++) {
        if (grades[i].grade >= 6) {
            double total_ects = 0.0;
            for (int j = 0; j < number_of_grades; j++) {
                if (strcmp(grades[i].fullname, grades[j].fullname) == 0) {
                    total_ects += grades[j].course.ects;
                }
            }

            if (total_ects >= 30) {
                int current_date_digits = count_different_digits(grades[i].date.day) +
                                           count_different_digits(grades[i].date.month) +
                                           count_different_digits(grades[i].date.year);

                for (int j = 0; j < number_of_grades; j++) {
                    if (strcmp(grades[i].fullname, grades[j].fullname) == 0 && j != i) {
                        int date_digits = count_different_digits(grades[j].date.day) +
                                          count_different_digits(grades[j].date.month) +
                                          count_different_digits(grades[j].date.year);

                        if (date_digits < current_date_digits) {
                            for (int k = j; k < number_of_grades - 1; k++) {
                                grades[k] = grades[k + 1];
                            }
                            number_of_grades--;
                            j--;  // Adjust the loop index after removal
                        }
                    }
                }
            }
        }
    }
    return number_of_grades;
}

int main() {
    int number_of_grades;
    printf("Enter the number of grades: ");
    scanf("%d", &number_of_grades);

    struct Grade *grades = (struct Grade *)malloc(number_of_grades * sizeof(struct Grade));

    printf("Enter grades:\n");
    for (int i = 0; i < number_of_grades; i++) {
        printf("Grade %d:\n", i + 1);
        printf("Full name: ");
        scanf("%s", grades[i].fullname);
        printf("Grade: ");
        scanf("%d", &grades[i].grade);
        printf("Course name: ");
        scanf("%s", grades[i].course.name);
        printf("ECTS: ");
        scanf("%lf", &grades[i].course.ects);
        printf("Date (day month year): ");
        scanf("%d %d %d", &grades[i].date.day, &grades[i].date.month, &grades[i].date.year);
    }

    digits_in_date(grades, number_of_grades);

    printf("\nGrades after filtering:\n");
    for (int i = 0; i < number_of_grades; i++) {
        printf("%s - %s - %.1f ECTS - %d.%d.%d\n", grades[i].fullname, grades[i].course.name,
               grades[i].course.ects, grades[i].date.day, grades[i].date.month, grades[i].date.year);
    }

    free(grades);

    return 0;
}

测试用例 #

测试用例1（输出正确） #

输入

struct Grade array[3] = {
    { "Mujo Suljic", 10, { 1, "Introduction to Programming", 25}, { 19, 1, 2020 } },
    { "Fata Fatic", 8, { 1, "Introduction to Programming", 25}, { 19, 1, 2020 } },
    { "Mujo Suljic", 7, { 2, "Engineering Physics 1", 10}, { 11, 1, 2020 } }
};

int size = digits_in_date(array, 3);

int i;
for (i = 0; i < size; i++)
    printf("%s %s\n", array[i].fullname, array[i].course.name);

预期输出

Mujo Suljic Introduction to Programming
Fata Fatic Introduction to Programming

我的输出

Mujo Suljic Introduction to Programming
Fata Fatic Introduction to Programming

失败测试用例 #

输入

struct Grade array[6] = {
    { "Mujo Suljic", 10, { 1, "Introduction to Programming", 25}, { 20, 2, 2020 } },
    { "Pero Peric", 6, { 5, "Fundamentals of Electrical Engineering", 25}, { 20, 2, 2020 } },
    { "Fata Fatic", 8, { 1, "Introduction to Programming", 25}, { 19, 1, 2020 } },
    { "Mujo Suljic", 5, { 2, "Engineering Physics 1", 10}, { 11, 1, 2020 } },
    { "Mujo Suljic", 10, { 3, "Engineering Mathematics 1", 4}, { 20, 1, 2020 } },
    { "Fata Fatic", 8, { 4, "Engineering Mathematics 1", 25}, { 19, 1, 2020 } }
};

int size = digits_in_date(array, 6);

int i;
for (i = 0; i < size; i++)
    printf("%s %s %g\n", array[i].fullname, array[i].course.name, array[i].course.ects);

预期输出

Mujo Suljic Introduction to Programming 25
Pero Peric Fundamentals of Electrical Engineering 25
Mujo Suljic Engineering Physics 1 10
Mujo Suljic Engineering Mathematics 1 4

我的输出

Mujo Suljic Introduction to Programming 25
Pero Peric Fundamentals of Electrical Engineering 25
Fata Fatic Introduction to Programming 25
Mujo Suljic Engineering Physics 1 10
Mujo Suljic Engineering Mathematics 1 4
Fata Fatic Engineering Mathematics 1 25

内容的提问来源于stack exchange，提问作者Irma Ibrović