java 求一组数组的波峰与波谷

Question

比如一组数【4,5,1,1,4,3,3,3,3,5,5,6,4,4,3,2】求他的波形图的波峰与波谷；结果应该是5,1,4,3,6 各位大神看看

Answer 1

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");
    }
   }
  }

Answer 2

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