算法-->分治

package 分治算法;

import java.util.Scanner;

public class fenzhi {
static final int MAXNUM=4;
static int falsecoin(int coin[],int low,int hight) {
 int i,num1,num2,num3;
 int re=0;
 num1=num2=num3=0;
 if(low+1==hight) {
  if(coin[low]   re=low+1;
  return re;
 }else {
  re=hight+1;
  return re;
 }
 }
  //如果是偶数
 if((hight-low+1)%2==0) {
 for(i=low;i<=low+(hight-low)/2;i++) {
  num1=num1+coin[i];//前面一半的和
 }
 for(i=low+(hight-low)/2+1;i<=hight;i++) {
  num2=num2+coin[i];//后面一半的和
 }
 if(num1   re=falsecoin(coin,low,low+(hight-low)/2);
  return re;
 }else if(num1>num2){
  re=falsecoin(coin,low+(hight-low)/2,hight);
  return re;
 }else {
  
 }
 }else {//是奇数
  for(i=low;i<=low+(hight-low)/2-1;i++) {
   num1=num1+coin[i];
  }
  for(i=low+(hight-low)/2+1;i<=hight;i++) {
   num2=num2+coin[i];
  }
  num3=coin[low+(hight-low)/2];
  if(num1>num2) {
   re=falsecoin(coin,low+(hight-low)/2+1,hight);
   return re;
  }else if(num1    re=falsecoin(coin,low,low+(hight-low)/2);
   return re;
  }else {
   
  }
  if(num1+num3==num2+num3) {
   re=low+(hight-low)/2+1;
   return re;
  }
 }
 return re;
}
 public static void  main(String []args) {
  int []coin=new int[MAXNUM];
  int i,n;
  int weizhi;
  System.out.println("分治算法求解假币问题");
  System.out.println("请输入硬币的总个数");
  Scanner sc=new  Scanner(System.in);
  n=sc.nextInt();
  System.out.println("请输入硬币的真假");
  for(i=0;i    coin[i]=sc.nextInt();//输入硬币的真假
  }
  weizhi=falsecoin(coin,0,n-1);
  System.out.println("在上述"+MAXNUM+"个硬币中，第"+weizhi+"个硬币是假币");
  }
}