Hzau 1203 One Stroke (dfs+ binary Or double pointer)

Test instructions: Give you a binary tree, point a bit of power, every time to the left or go to the right, to find the longest way to go, and point right and less than K;

Idea: The official solution, ruler take, my writing, two points on the tree,

For a chain, enumerate each point as the end point, vector the point to the root node prefix and, two minutes can be;

See Code;

　　

Learn from the user code.

#pragma COMMENT (linker, "/stack:1024000000,1024000000") #include <iostream> #include <cstdio> #include <cmath> #include <string> #include <queue> #include <algorithm> #include <stack> #include <cstring> #include <vector> #include <list> #include <set> #include <map> using namespace
Std
#define LL Long Long #define PI (4*atan (1.0)) #define EPS 1e-4 #define BUG (x) cout<< "Bug" <<x<<endl;
const int n=1e6+10,m=1e6+10,inf=2147483647;
 
const LL inf=1e18+10,mod=2147493647;
Array size int n,ans,k,a[n];
vector<int>v;
    void Dfs (int x) {int s=0,t=v.size ()-1;
    int e=v.size () -1,ansq=-1;
        while (s<=e) {int mid= (s+e) >>1;
            if (v[t]-v[mid]<=k) {ansq=mid;
        E=mid-1;
    } else s=mid+1;
    } if (v[t]<=k) Ans=max (ans,t+1);
    else Ans=max (ANS,T-ANSQ);
    int Z=v[v.size ()-1]; if (x*2<=n) {v.push_back (z+a[x<<1]);
        DFS (X&LT;&LT;1);
    V.pop_back ();
        } if (x*2+1<=n) {v.push_back (z+a[x<<1|1]);
        DFS (X&LT;&LT;1|1);
    V.pop_back ();
    }} int main () {int T;
    scanf ("%d", &t);
        while (t--) {ans=0;
        V.clear ();
        scanf ("%d%d", &n,&k);
        for (int i=1;i<=n;i++) scanf ("%d", &a[i]);
        V.push_back (a[1]);
        DFS (1);
        if (ans) printf ("%d\n", ans);
    else printf (" -1\n");
} return 0; }