配列内の左加算と右加算の和に等しい数値を見つけます.

  public static void demo1(int arr[]){
        int length = arr.length;
        int leftTotal = 0;
        int rightTotal = 0;
        for(int i=1;iif(i==1){
                leftTotal = arr[0];
                for(int j=i+1;jelse{
                leftTotal = leftTotal+arr[i-1];
                rightTotal = rightTotal-arr[i];
            }
                                    System.out.println("===>i="+i+"=====>leftTotal="+leftTotal+"=====>rightTotal="+rightTotal);
            if(leftTotal == rightTotal){
                System.out.println(arr[i]);
            }
        }
    }

 public static void splitFind(int arr[]){

        int length  = arr.length;
        int head,tail,index;    

        head = 0;
        tail = length - 1;  //         
        index = length / 2;//    

        int total = 0;  //          
        for(int i :arr){
            total += i;
        }
        do{
            int leftTotal = 0;
            //           
            for(int le = 0;le <index ;le ++){
                leftTotal += arr[le];
            }
            //        -       
            int doubleValue=(total - arr[index]);
            if(leftTotal*2 index;
                index = index + (length - index) / 2;
            }else if(leftTotal*2 >doubleValue){
                total = index;
                index = head + (index - head) / 2;
            }else{
                System.out.println(index);
                return  ;
            }
        }while(index > head && index 

 public static void splitFind2(int arr[]){

        int length  = arr.length;
        int head,tail,index;    

        head = 0;
        tail = length - 1;  //         
        index = length >> 1;//    

        int total = 0;  //          
        for(int i :arr){
            total += i;
        }
        do{
            int leftTotal = 0;
            //           
            for(int le = 0;le <index ;le ++){
                leftTotal += arr[le];
            }
            //        -       
            int doubleValue=(total - arr[index]);
            if(leftTotal<<1 index;
                index = index + (length - index) >>1;
            }else if(leftTotal<<1 >doubleValue){
                total = index;
                index = head + (index - head)  >>1;
            }else{
                System.out.println(index);
                return  ;
            }
        }while(index > head && index