Arrays Bucketing 1

 public int repeatedNumber(final int[] arr) {
        int n = arr.length;
        for(int i=0;i<n;i++){
            arr[i] = arr[i]-1;
        }
        for(int i=0;i<n;i++){
            arr[(arr[i])%n] = arr[(arr[i])%n]+n;
        }
        for(int i=0;i<n;i++){
            //System.out.println()
            if(arr[i]/n > 1){
                return i+1;
            }
        }
        return -1;
    }