comefrom: <qiyuangong>852_Peak_Index_in_a_Mountain_Array_2.java
code: public int peakIndexInMountainArray(int[] A) {
          int lo = 0, hi = A.length - 1;
          while (lo < hi) {
              int mid = (lo + hi) / 2;
              if (A[mid] < A[mid + 1]) lo = mid + 1;
              else hi = mid;
          }
          return lo;
      }
masked: public int sample_funcname ( int [ ] var_0 ) {
    int var_1 = 0 , var_2 = var_0 . length - 1 ;
    while ( var_1 < var_2 ) {
      int var_3 = ( var_1 + var_2 ) / 2 ;
      if ( var_0 [ var_3 ] < var_0 [ var_3 + 1 ] ) var_1 = var_3 + 1 ;
      else var_2 = var_3 ;
    }
    return var_1 ;
  }
  