Enter the depth of a two-fork tree and its three nodes, and find the root node of the three-node tree.

For example: the input depth is 4, the three subnodes are 10,13,15, and the minimum subtree is 12.

We can infer that this is a median traversal value from 1 to 2^k-1 according to the tree traversal method.

We can use the binary search technology to find the root node of the oldest tree.

[CPP]  View plain  copy//based on two-point search    #include <algorithm>   #include <cmath>    Int findmin (int* arr,int left,int right)    {        int mid= ((right-left) >>1) +left;       if (arr[0]<=mid& &arr[2]>=mid)            return mid;       else if (arr[0]>mid)             return findmin (arr,mid+1,right);       else if (Arr[2]<mid)            return findmin (arr,left,mid-1);  }    void test2 ()    {       int k=0;        cin>>k;       int arr[3];       &nbsP;for (int i=0;i<3;++i)        {            cin>>arr[i];         }        sort (arr,arr+3);       int right= (1<<k) -1; //move 1 to the left K-bit, = = = "2^k       int min=findmin (arr,1,right);        cout<<min<<endl;  }