byte[] wave = new byte[]{4,5,1,1,4,3,3,3,3,5,5,6,4,4,3,2};
        int direction = wave[0] > 0? -1:1;
          for(int i=0;i<wave.length-1;i++) {
           if((wave[i+1]-wave[i])*direction>0) {
            direction*=-1;
            if(direction == 1) {
             System.out.println("("+i+","+wave[i]+")"+"波峰");
            } else {
             System.out.println("("+i+","+wave[i]+")"+"波谷");
            }
           }
          }

------解决方案--------------------
用数组，如果array[i+1]是波峰或波谷的话，array[i+1]-array[i] 与array[i+2]-array[i+1]异号

------解决方案--------------------
波峰比附近的值都大，波谷比附近的值都小。。。