Notes

int numAssignment = s.nextInt(); // number of assignments
double assignmentTotal = 0.0; // total points possible
for (int i = 0; i < numAssignment; i++) {
assignmentTotal += s.nextDouble(); // adds each assignment weight
}
double participationTotal = s.nextDouble(); // max possible participation points
int numStudents = s.nextInt(); // number of students

// arrays for each section of the total grade
double[] assignments = new double[numStudents];
double[] participation = new double[numStudents];
double[] midterm = new double[numStudents];
double[] finalExam = new double[numStudents];

for (int i = 0; i < numStudents; i++) { // puts grades for each student in array
s.next();
s.next();
participation[i] = (s.nextDouble() / (participationTotal * 0.8)) * 100;
if (participation[i] > 100) {
participation[i] = 100;
}
assignments[i] = 0.0;
for (int j = 0; j < numAssignment; j++) {
assignments[i] += s.nextDouble();
}
assignments[i] = (assignments[i] / assignmentTotal) * 100;
midterm[i] = s.nextDouble();
finalExam[i] = s.nextDouble();
}
// converts to normalized scores
double[] normalizedFinal = new double[numStudents];
double[] normalizedMidterm = new double[numStudents];
for (int i = 0; i < numStudents; i++) { // for final exam and midterm
normalizedFinal[i] = (finalExam[i] - average(finalExam)) / findSD(finalExam, average(finalExam));
normalizedMidterm[i] = (midterm[i] - average(midterm)) / findSD(midterm, average(midterm));
}
// adds curve to grade
double[] curved = new double[numStudents];
curved = curve(normalizedFinal);
double[] curvedMidterm = new double[numStudents];
curvedMidterm = curve(normalizedMidterm);

// multiplies grade by weights
String[] grades = new String[numStudents];
for (int i = 0; i < grades.length; i++) {
grades[i] = toLetter((participation[i] * 0.15) + (assignments[i] * 0.4) + (curvedMidterm[i] * 0.2) + (curved[i] * 0.25));
}

// prints each count of a grade
System.out.println("A : " + search(grades, "A"));
System.out.println("A-: " + search(grades, "A-"));
System.out.println("B+: " + search(grades, "B+"));
System.out.println("B : " + search(grades, "B"));
System.out.println("B-: " + search(grades, "B-"));
System.out.println("C+: " + search(grades, "C+"));
System.out.println("C : " + search(grades, "C"));
System.out.println("C-: " + search(grades, "C-"));
System.out.println("D+: " + search(grades, "D+"));
System.out.println("D : " + search(grades, "D"));
System.out.println("F : " + search(grades, "F"));
}

// converts number grade to letter grade
public static String toLetter(double grade) {

if (grade >= 94) {
return ("A");
} else if (grade >= 90) {
return ("A-");
} else if (grade >= 86) {
return ("B+");
} else if (grade >= 83) {
return ("B");
} else if (grade >= 80) {
return ("B-");
} else if (grade >= 76) {
return ("C+");
} else if (grade >= 73) {
return ("C");
} else if (grade >= 70) {
return ("C-");
} else if (grade >= 65) {
return ("D+");
} else if (grade >= 60) {
return ("D");
} else {
return ("F");
}
}

// calculates average
public static double average(double[] list) {
double sum = 0.0;
double avg = 0.0;
for (int i = 0; i < list.length; i++) {
sum += list[i];
avg = sum / list.length;
}
return avg;
}

// finds standard deviation
public static double findSD(double[] list, double average) {
double[] dev = new double[list.length];
for (int i = 0; i < list.length; i++) {
dev[i] = Math.pow(average - list[i], 2);
}
double sd = Math.sqrt(average(dev));
return sd;
}

// curves grades according to normalized score
public static double[] curve(double[] normalized) {
double[] grade = new double[normalized.length];
for (int i = 0; i < normalized.length; i++) {
double x = normalized[i];

if (x >= 2.0) {
grade[i] = 100.0;
} else if (x < 2.0 && x > 1.0) {
grade[i] = (((x - 1.0) / (2.0 - 1.0)) * (100.0 - 94.0)) + 94.0;
} else if (x == 1.0) {
grade[i] = 94;
} else if (x < 1.0 && x > 0) {
grade[i] = (((x - 0) / (1.0 - 0)) * (94.0 - 85.0)) + 85.0;
} else if (x == 0) {
grade[i] = 85.0;
} else if (x < 0 && x > -1.0) {
grade[i] = (((x + 1.0) / (0 + 1.0)) * (85.0 - 75.0)) + 75.0;
} else if (x == -1.0) {
grade[i] = 75.0;
} else if (x < -1.0 && x > -1.5) {
grade[i] = (((x + 1.5) / (-1.0 + 1.5)) * (75.0 - 65.0)) + 65.0;
} else if (x == -1.5) {
grade[i] = 65.0;
} else if (x < -1.5 && x > -2.0) {
grade[i] = (((x + 2.0) / (-1.5 + 2.0)) * (65.0 - 55.0)) + 55.0;
} else if (x == -2.0) {
grade[i] = 55.0;
} else if (x < -2.0 && x > -3.0) {
grade[i] = (((x + 3.0) / (-2.0 + 3.0)) * (55.0 - 30.0)) + 30.0;
} else if (x == -3.0) {
grade[i] = 30.0;
} else if (x < -3.0 && x > -4.0) {
grade[i] = ((x + 4.0) / (-3.0 + 4.0)) * 30.0;
} else {
grade[i] = 0.0;
}
}
return grade;
}

// checks if strings are equal
public static int search(String[] array, String str) {
int total = 0;
for (int i = 0; i < array.length; i++) {
if (array[i].equals(str)) {
total++;
}
}
return total;
}
}