hdu 6983 / 2021“MINIEYE杯”中国大学生算法设计超级联赛（3）1011 Segment Tree with Pruning

https://acm.hdu.edu.cn/showproblem.php?pid=6983

 

节点代表的区间长度只有log种，记忆化搜索

 

#include<bits/stdc++.h>

using namespace std;

map<long long,long long>mp;

long long dfs(long long n,long long k)
{
    if(n<=k) return 1;
    if(mp.find(n)==mp.end()) mp[n]=dfs(n>>1,k)+dfs(n-(n>>1),k)+1;
    return mp[n];
}

int main()
{
    int T;
    long long n,k;
    scanf("%d",&T);
    while(T--)
    {
        scanf("%lld%lld",&n,&k);
        mp.clear();
        printf("%lld\n",dfs(n,k));
    }    
}