Task: Top rank per group

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

typedef struct {
    const char *name, *id, *dept;
    int sal;
} person;

person ppl[] = {
    {"Tyler Bennett",   "E10297", "D101", 32000},
    {"John Rappl",      "E21437", "D050", 47000},
    {"George Woltman",  "E00127", "D101", 53500},
    {"Adam Smith",      "E63535", "D202", 18000},
    {"Claire Buckman",  "E39876", "D202", 27800},
    {"David McClellan", "E04242", "D101", 41500},
    {"Rich Holcomb",    "E01234", "D202", 49500},
    {"Nathan Adams",    "E41298", "D050", 21900},
    {"Richard Potter",  "E43128", "D101", 15900},
    {"David Motsinger", "E27002", "D202", 19250},
    {"Tim Sampair",     "E03033", "D101", 27000},
    {"Kim Arlich",      "E10001", "D190", 57000},
    {"Timothy Grove",   "E16398", "D190", 29900},
};

int pcmp(const void *a, const void *b)
{
    const person *aa = a, *bb = b;
    int x = strcmp(aa->dept, bb->dept);
    if (x) return x;
    return aa->sal > bb->sal ? -1 : aa->sal < bb->sal;
}

#define N sizeof(ppl)/sizeof(person)
void top(int n)
{
    int i, rank;
    qsort(ppl, N, sizeof(person), pcmp);

    for (i = rank = 0; i < N; i++) {
        if (i && strcmp(ppl[i].dept, ppl[i - 1].dept)) {
            rank = 0;
            printf("\n");
        }

        if (rank++ < n)
            printf("%s %d: %s\n", ppl[i].dept, ppl[i].sal, ppl[i].name);
    }
}

int main()
{
    top(2);
    return 0;
}




Go: package main

import (
    "fmt"
    "sort"
)


type Employee struct {
    Name, ID string
    Salary   int
    Dept     string
}

type EmployeeList []*Employee

var data = EmployeeList{
    {"Tyler Bennett", "E10297", 32000, "D101"},
    {"John Rappl", "E21437", 47000, "D050"},
    {"George Woltman", "E00127", 53500, "D101"},
    {"Adam Smith", "E63535", 18000, "D202"},
    {"Claire Buckman", "E39876", 27800, "D202"},
    {"David McClellan", "E04242", 41500, "D101"},
    {"Rich Holcomb", "E01234", 49500, "D202"},
    {"Nathan Adams", "E41298", 21900, "D050"},
    {"Richard Potter", "E43128", 15900, "D101"},
    {"David Motsinger", "E27002", 19250, "D202"},
    {"Tim Sampair", "E03033", 27000, "D101"},
    {"Kim Arlich", "E10001", 57000, "D190"},
    {"Timothy Grove", "E16398", 29900, "D190"},
    
    {"Tie A", "E16399", 29900, "D190"},
    {"Tie B", "E16400", 29900, "D190"},
    {"No Tie", "E16401", 29899, "D190"},
}









type By func(e1, e2 *Employee) bool
type employeeSorter struct {
    list EmployeeList
    by   func(e1, e2 *Employee) bool
}

func (by By) Sort(list EmployeeList)         { sort.Sort(&employeeSorter{list, by}) }
func (s *employeeSorter) Len() int           { return len(s.list) }
func (s *employeeSorter) Swap(i, j int)      { s.list[i], s.list[j] = s.list[j], s.list[i] }
func (s *employeeSorter) Less(i, j int) bool { return s.by(s.list[i], s.list[j]) }










func (el EmployeeList) TopSalariesByDept(n int) []EmployeeList {
    if n <= 0 || len(el) == 0 {
        return nil
    }
    deptSalary := func(e1, e2 *Employee) bool {
        if e1.Dept != e2.Dept {
            return e1.Dept < e2.Dept
        }
        if e1.Salary != e2.Salary {
            return e1.Salary > e2.Salary
        }
        
        return e1.ID < e2.ID
    }

    
    
    
    
    sorted := make(EmployeeList, len(el))
    copy(sorted, el)
    By(deptSalary).Sort(sorted)

    perDept := []EmployeeList{}
    var lastDept string
    var lastSalary int
    for _, e := range sorted {
        if e.Dept != lastDept || len(perDept) == 0 {
            lastDept = e.Dept
            perDept = append(perDept, EmployeeList{e})
        } else {
            i := len(perDept) - 1
            if len(perDept[i]) >= n && e.Salary != lastSalary {
                continue
            }
            perDept[i] = append(perDept[i], e)
            lastSalary = e.Salary
        }
    }
    return perDept
}

func main() {
    const n = 3
    top := data.TopSalariesByDept(n)
    if len(top) == 0 {
        fmt.Println("Nothing to show.")
        return
    }
    fmt.Printf("Top %d salaries per department\n", n)
    for _, list := range top {
        fmt.Println(list[0].Dept)
        for _, e := range list {
            fmt.Printf("    %s %16s %7d\n", e.ID, e.Name, e.Salary)
        }
    }
}