package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

func main() {
  file, _ := os.Open("test")
//  file, _ := os.Open("input")
  defer file.Close()
  scanner := bufio.NewScanner(file)
  diskMap := []string{}
  for scanner.Scan() {
    line := scanner.Text()
    diskMap = append(diskMap, strings.Split(line, "")...)
  }
  fileID := 0
  blockSize := 0
  blockSizes := []int{}
  freeSpace := 0
  freeSpaces := []int{}
  blocks := []string{}
  for i := range diskMap {
    if i % 2 == 0 {
      blockSize, _ = strconv.Atoi(diskMap[i])
      blockSizes = append(blockSizes, blockSize)
      for j:=0;j<blockSize;j++ {
        blocks = append(blocks, strconv.Itoa(fileID))
      }
      fileID++
    } else {
      freeSpace, _ = strconv.Atoi(diskMap[i])
      freeSpaces = append(freeSpaces, freeSpace)
      for j:=0;j<freeSpace;j++ {
        blocks = append(blocks, ".")
      }
    }
  }
//  for i := range blocks {
//    if blocks[i] == "." {
//      for j:=len(blocks)-1;j>i;j-- {
//        if blocks[j] != "." {
//          blocks[i] = blocks[j]
//          blocks[j] = "."
//          break
//        }
//      }
//    }
//  }
//  checksum := 0
//  for i := range blocks {
//    blockID, _ := strconv.Atoi(blocks[i])
//    checksum = checksum + i * blockID
//  }
//  fmt.Println(checksum)
  fmt.Println(blocks)
//  moved := []bool{}
//  for i:=0;i<fileID;i++ {
//    moved = append(moved, false)
//  }
//  for id:=fileID-1;id>=0;id-- {
//    for j:=0;j<id;j++{
//      fmt.Println("1.", blockSizes[id], "<=", freeSpaces[j])
//      if blockSizes[id] <= freeSpaces[j] {
//        for k:=len(blocks)-1;k>=0;k-- {
//          if blocks[k] == strconv.Itoa(j) {
//            fmt.Println("2. k:", k, "blocks[k]:", blocks[k])
//            changed := []int{}
//            for l:=0;l<blockSizes[id];l++ {
//              emptyPosition := 0
//              found := false
//              for ! found {
//                if blocks[k+emptyPosition+1+l] == "." {
//                  found = true
//                  break
//                } else {
//                  emptyPosition++
//                }
//              }
//              blocks[k+emptyPosition+1+l] = strconv.Itoa(id)
//              fmt.Println(blocks)
//              changed = append(changed, k+1+l)
//            }
//            for x1:=0;x1<len(blocks);x1++ {
//              if blocks[x1] == strconv.Itoa(id) && ! slices.Contains(changed, x1) {
//                blocks[x1] = "."
//              }
//            }
//            fmt.Println("3.1 before", freeSpaces[j])
//            freeSpaces[j] = freeSpaces[j]-blockSizes[id]
//            fmt.Println("3.2 after", freeSpaces[j])
//            moved[id] = true
//            break
//          }
//        }
//      }
//      if moved[id] {
//        break
//      }
//    }
//  }
//  fmt.Println(blocks)
  //TRY2
  for id:=fileID-1;id>=0;id-- {
    idPositions := findIDpositions(blocks, id)
    for i:=0;i<fileID-1;i++ {
      spacesPositionsAfterID := findSpacesAfterID(blocks, i)
      if len(idPositions) <= len(spacesPositionsAfterID) {
        for i:=0;i<len(spacesPositionsAfterID);i++ {
          blocks[spacesPositionsAfterID[i]] = strconv.Itoa(id)
          fmt.Println(blocks)
        }
        for i:=0;i<len(idPositions);i++ {
          blocks[idPositions[i]] = "."
          fmt.Println(blocks)
        }
        break
      }
    }
  }
  fmt.Println(blocks)
}


func findIDpositions(blocks []string, id int) []int {
  positions := []int{}
  for i := range blocks {
    if blocks[i] == strconv.Itoa(id) {
      positions = append(positions, i)
    }
  }
  return positions
}

func findSpacesAfterID(blocks []string, id int) []int {
  spaces := []int{}
  idPositions := findIDpositions(blocks,id)
  for i:=idPositions[len(idPositions)-1];i<len(blocks);i++ {
    if blocks[i] == "." {
      spaces = append(spaces, i)
    }
  }
  return spaces
}