18

来源：互联网发布：java个人信息管理系统编辑：程序博客网时间：2024/04/29 11:56
package scalaCode/**  * Created by zp on 2017/7/13.  */package leetcodeimport scala.collection.mutable.ListBufferimport scala.util.control.Breaksobject FourSum {  def twoSumForFourSum(nums: Array[Int], target: Int, start: Int, res: ListBuffer[ListBuffer[Int]], z1: Int, z2: Int): Unit = {    val high = nums.size - 1    if (start >= high) {      return None    }    if (2 * nums(start) > target || 2 * nums(high) < target){      return None    }    var i = start    var j = high    var sum = 0    var x = 0    while (i < j){      sum = nums(i) + nums(j)      if (sum == target){        val tmp = new ListBuffer[Int]        tmp += (z1, z2, nums(i), nums(j))        res += tmp        x = nums(i)        while (i < j && nums(i) == x) {i += 1}        x = nums(j)        while (i < j && nums(j) == x) {j -= 1}      }      if (sum < target){        i += 1      }      if (sum > target) {        j -= 1      }    }  }  def threeSumFourSum(nums: Array[Int], target: Int, start : Int, res: ListBuffer[ListBuffer[Int]], z1: Int) {    val high = nums.size - 1    val max = nums(high)    //异常情况    if (3 * nums(start) > target || 3 * max < target){      return    }    var first = new Breaks    var second = new Breaks    var thrid = new Breaks    var loop = new Breaks    var z = 0    loop.breakable{      for (i <- start to high){        z = nums(i)        first.breakable{          if (i > start && z == nums(i - 1)){            first.break()          }        }        second.breakable{          if (z + 2 * max < target) {            second.break()          }        }        thrid.breakable{          if (3 * z > target){            thrid.break()          }        }        if ( 3 * z == target) {          if (i + 2 <= high && nums(i + 2) == z){            val tmp = new ListBuffer[Int]            tmp += (z1, z, z, z)            res += tmp          }          else {            loop.break()          }        }        twoSumForFourSum(nums, target - z, i + 1, res, z1, z )      }    }  }  def fourSum(ns: Array[Int], target: Int): List[List[Int]] = {    val res = new ListBuffer[ListBuffer[Int]]    //异常情况    if (ns == None || ns.size < 4) {      return (for (l <- res) yield l.toList).toList    }    //默认排序    var nums = for(n <- ns.sorted) yield n    //临界情况    val max = nums(nums.size - 1)    val min = nums(0)    if (4 * min > target || 4 * max < target) {      return (for (l <- res) yield l.toList).toList    }    var first = new Breaks    var second = new Breaks    var thrid = new Breaks    var loop = new Breaks    var z = 0    loop.breakable{      for (i <- 0 to nums.size - 1) {        z = nums(i)        first.breakable {          //避免重复,continue          if (i > 0 && z == nums(i - 1)) {            first.break()          }          //z太小          if (z + 3 * max < target) {            first.break()          }          //z太大          if (4 * z > target) {            first.break()          }        }        //边界情况        if (4 * z == target) {          if (i + 3 < nums.size && nums(i + 3) == z) {            val tmp = new ListBuffer[Int]            tmp += (z, z, z, z)            res += tmp          } else {            loop.break()          }        }        threeSumFourSum(nums, target - z, i + 1, res, z)      }    }    (for (l <- res) yield l.toList).toList  }  def main(args: Array[String]): Unit = {    var a = Array(1, 0, -1, 0, -2, 2)    println(fourSum(a, 0))  }}
阅读全文
0 0