Golang每日一练(leetDay0096) 添加运算符、移动零

package main
import (
  "fmt"
  "strconv"
)
func addOperators(num string, target int) []string {
  res := []string{}
  var dfs func(expr string, cur, prev, sum int)
  dfs = func(expr string, cur, prev, sum int) {
    if cur == len(num) {
      if sum == target {
        res = append(res, expr)
      }
      return
    }
    for i := cur; i < len(num); i++ {
      if i != cur && num[cur] == '0' {
        break
      }
      val, _ := strconv.Atoi(num[cur : i+1])
      if cur == 0 {
        dfs(num[:i+1], i+1, val, val)
        continue
      }
      dfs(expr+"+"+num[cur:i+1], i+1, val, sum+val)
      dfs(expr+"-"+num[cur:i+1], i+1, -val, sum-val)
      dfs(expr+"*"+num[cur:i+1], i+1, prev*val, sum-prev+prev*val)
    }
  }
  dfs("", 0, 0, 0)
  return res
}
func main() {
  fmt.Println(addOperators("123", 6))           // ["1+2+3" "1*2*3"]
  fmt.Println(addOperators("232", 8))           // ["2+3*2" "2*3+2"]
  fmt.Println(addOperators("3456237490", 9191)) // []
}

package main
import "fmt"
func moveZeroes(nums []int) {
  n := len(nums)
  j := 0 // 非零元素应该插入的位置
  for i := 0; i < n; i++ {
    if nums[i] != 0 {
      nums[j], nums[i] = nums[i], nums[j] // 交换位置
      j++
    }
  }
}
func moveZeroes2(nums []int) {
  n := len(nums)
  j := 0 // 非零元素的个数
  for i := 0; i < n; i++ {
    if nums[i] != 0 {
      nums[j] = nums[i]
      if i != j {
        nums[i] = 0
      }
      j++
    }
  }
}
func main() {
  nums := []int{0, 1, 0, 3, 12}
  moveZeroes(nums)
  fmt.Println(nums) // [1 3 12 0 0]
  nums = []int{0, 1, 0, 3, 12}
  moveZeroes2(nums)
  fmt.Println(nums) // [1 3 12 0 0]
  nums2 := []int{0}
  moveZeroes2(nums2)
  fmt.Println(nums2) // [0]
}