zstu19一月月赛 duxing201606的原味鸡树
题意:
给定一颗有n(n<=1e9)个节点的完全二叉树,1e5次询问,问某个节点有几个子节点。
思路:
自己在月赛上没有思路,问了zfq才知道。
设两个指标,L、R,因为是范围,所以每次L向左孩子一直下去,R向右孩子一直下去,每次下探答案就要加上2的i次,L~R间就是根节点所表示的范围。当n出了L,R区间,退出。
#include <algorithm> #include <iterator> #include <iostream> #include <cstring> #include <cstdlib> #include <iomanip> #include <bitset> #include <cctype> #include <cstdio> #include <string> #include <vector> #include <stack> #include <cmath> #include <queue> #include <list> #include <map> #include <set> #include <cassert> using namespace std; #define lson (l , mid , rt << 1) #define rson (mid + 1 , r , rt << 1 | 1) #define debug(x) cerr << #x << " = " << x << "\n"; #define pb push_back #define pq priority_queue typedef long long ll; typedef unsigned long long ull; //typedef __int128 bll; typedef pair<ll ,ll > pll; typedef pair<int ,int > pii; typedef pair<int,pii> p3; //priority_queue<int> q;//这是一个大根堆q //priority_queue<int,vector<int>,greater<int> >q;//这是一个小根堆q #define fi first #define se second //#define endl '\n' #define OKC ios::sync_with_stdio(false);cin.tie(0) #define FT(A,B,C) for(int A=B;A <= C;++A) //用来压行 #define REP(i , j , k) for(int i = j ; i < k ; ++i) #define max3(a,b,c) max(max(a,b), c); #define min3(a,b,c) min(min(a,b), c); //priority_queue<int ,vector<int>, greater<int> >que; const ll mos = 0x7FFFFFFF; //2147483647 const ll nmos = 0x80000000; //-2147483648 const int inf = 0x3f3f3f3f; const ll inff = 0x3f3f3f3f3f3f3f3f; //18 const int mod = 9999973; const double esp = 1e-8; const double PI=acos(-1.0); const double PHI=0.61803399; //黄金分割点 const double tPHI=0.38196601; template<typename T> inline T read(T&x){ x=0;int f=0;char ch=getchar(); while (ch<'0'||ch>'9') f|=(ch=='-'),ch=getchar(); while (ch>='0'&&ch<='9') x=x*10+ch-'0',ch=getchar(); return x=f?-x:x; } /*-----------------------showtime----------------------*/ int main(){ int n;int m; scanf("%d%d", &n, &m); for(int i=1; i<=m; i++){ int x; scanf("%d", &x); int l=x,r=x; ll res = 0,now = 1; for(;;){ l = l*2; r = r*2+1; res = res + now; now = now * 2; if( l<= n && n<r){ res += n - l + 1; break; } if( n < l) break; } printf("%lld\n", res); } return 0; }
skr