"Algorithm Learning" method of three points

We all know the binary search and the application of many binary points.

However, the two points are mainly used for functions or sequences with monotonicity.

If the function/sequence is not monotonic, it has a single-peak/Valley feature.

We can use the three-point method to determine the extremum of this function.

The specific ideas of the three-part method can be seen elsewhere.

I put a template of my own, no bug ...

Because I used to be a bug template entrap ...

The speed is very fast and the constants should be very small. About twice times the constant of two points.

1L=l,r=r;//determine the initial value of l,r, ensure l<=r oh2  while(l!=R) {3     if(r-l<3){//[L,r] more than 3 on the special award4Ans=max4 (Ans,f (i,l), F (i,l+1), F (i,r));5          Break;6     }7mid1= (L+R)/2, mid2=mid1+1;//close the two point to the midpoint and decrease the constant8Val1=f (I,MID1), val2=f (I,MID2);9     if(VAL1&GT;=VAL2) r=Mid2;Ten     if(VAL1&LT;=VAL2) l=Mid1; One } A if(L==R) Ans=max (Ans,f (i,l));//for the l==r at the beginning of the contract

Algorithm learning three-part method