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package main
/* tested with:
* go run ch-1.go 1.1 0.8 0.4 0.2 2.3 1.1 0.4 0.9 4.3
* 1 as 1.0 < (0.200 + 0.400 + 0.800) < 2.0
*/
import (
"os"
"fmt"
"strconv"
"strings"
"sort"
)
func usage () {
fmt.Println( "Usage: go run ch-1.go <real numbers> ..." );
}
type combiIter struct {
dlen int // data length
nsel int // number of selection
ncsr int // next cursor
room []int
pos []int
}
// adapted from challenge-083/jeongoon/ch-2.go
// this combinations implentation keep the status into combiIter
// and give next combination when calling nextIndices()
func lazyCombinationsIndex( M int, N int ) *combiIter {
iter := &combiIter{
M,
N,
N-1,
make([]int, N),
make([]int, N),
}
initRoomSize := M - N
for i := 0; i < (N-1); i++ {
iter.room[i] = initRoomSize
iter.pos[i] = i
}
// note: we'll increase when nextIdices() called for the first time.
iter.room[N-1] = initRoomSize + 1
iter.pos[N-1] = N - 2;
return iter
}
func (ci *combiIter) nextIndices() []int {
var new_case []int
if ci.room[ci.ncsr] > 0 {
ci.room[ci.ncsr]--
ci.pos[ci.ncsr]++
new_case = make([]int, ci.nsel)
copy(new_case, ci.pos)
return new_case
} else {
cursor_moved := false
for i := ci.ncsr; i > 0; i-- {
if ci.room[i-1] > 0 {
ci.ncsr = i - 1;
cursor_moved = true
break
}
}
if cursor_moved {
new_room := ci.room[ci.ncsr] - 1
base_pos := ci.pos[ci.ncsr];
for p, i := 1, ci.ncsr; i < ci.nsel; i++ {
ci.room[i] = new_room
ci.pos[i] = base_pos + p
p++
}
new_case = make([]int, ci.nsel)
copy(new_case, ci.pos)
ci.ncsr = ci.nsel - 1
} else {
new_case = []int{}
}
}
return new_case
}
func parseStringsToFloat64s( args []string ) []float64 {
var result []float64
for i, maybe_f := range args {
f, err := strconv.ParseFloat(maybe_f, 64)
if err == nil {
result = append(result, f)
} else {
fmt.Fprintf(os.Stderr,
"wrong float value: [%d] [%s]\n", i, maybe_f)
}
}
return result
}
func tidyList( flist []float64 ) []float64 {
var result []float64
sorted := flist // copy
sort.Float64s(sorted) // sort (in place)
// only numbers < 2.0
for _, f := range(sorted) {
if f < 2.0 {
result = append(result, f)
}
}
return result
}
func main() {
if len(os.Args[1:]) < 3 {
usage();
os.Exit(1);
}
flist_ := parseStringsToFloat64s(os.Args[1:])
flist := tidyList( flist_ )
it := lazyCombinationsIndex(len(flist), 3)
var foundTripletStrs []string
for {
tripletIndices := it.nextIndices();
if len(tripletIndices) == 0 {
break
}
sum := 0.0;
for _, idx := range( tripletIndices ) {
sum += flist[idx]
}
if sum > 1.0 && sum < 2.0 {
for _, idx := range( tripletIndices ) {
fStr := strconv.
FormatFloat(flist[idx], 'f', 3, 64)
foundTripletStrs = append(foundTripletStrs,fStr)
}
break
}
}
if len(foundTripletStrs) == 0 {
fmt.Println("0");
os.Exit(2);
} else {
fmt.Println("1 as 1.0 < (" +
strings.Join(foundTripletStrs, " + ") +
") < 2.0")
os.Exit(0);
}
}
|
