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_2 = 0 , var_5 = var_0 . length - 1 ;
    while ( var_2 < var_5 ) {
      int var_7 = ( var_2 + var_5 ) / 2 ;
      if ( var_0 [ var_7 ] < var_0 [ var_7 + 1 ] ) var_2 = var_7 + 1 ;
      else var_5 = var_7 ;
    }
    return var_2 ;
  }
  