zyb的面试
http://acm.hdu.edu.cn/contests/contest_showproblem.php?pid=1008&cid=843
題解：模板題
/* *@Author: STZG *@Language: C++ */ #include <bits/stdc++.h> #include<iostream> #include<algorithm> #include<cstdlib> #include<cstring> #include<cstdio> #include<string> #include<vector> #include<bitset> #include<queue> #include<deque> #include<stack> #include<cmath> #include<list> #include<map> #include<set> //#define DEBUG #define RI register int using namespace std; typedef long long ll; //typedef __int128 lll; const int N=100000+10; const int M=100000+10; const int MOD=1e9+7; const double PI = acos(-1.0); const double EXP = 1E-8; const int INF = 0x3f3f3f3f; int t,n,m,k,q; int ans,cnt,flag,temp,sum; int a[N]; char str; struct node{};int findKthNumber(int n, int k) {//*************************//第一部分，得到樹群的最大深度。if (n<10)return k;int sum = 9;int base = 1;int deep = 0;while (n>sum) {base *= 10;++deep;sum += 9 * base;}//*************************//第二部分，確定k在左側樹群還是在右側樹群。int redund = n - (base - 1);int lisNum = redund;while (base != 1) {n /= 10;base /= 10;int tmp = n - (base - 1);//cout << tmp << endl;lisNum += tmp;}if (k > lisNum) {--deep;k -= redund;}//*************************//第三部分，在k所歸屬的樹中找到其值。//cout<<" +"<<endl;int partSum = 0;vector<int>work(deep + 1, 0);for (int i = 0; i <= deep; ++i) {partSum += pow(10, i);work[deep - i] = partSum;}int seq = (k - 1) / partSum + 1;int rem = (k - 1) % partSum;string result;result.push_back('0' + seq);for (int i = 1; i <= deep && rem != 0; ++i) {--rem;int order = rem / work[i];rem = rem % work[i];result.push_back('0' + order);}return stoi(result);}int main() { #ifdef DEBUGfreopen("input.in", "r", stdin);//freopen("output.out", "w", stdout); #endif//ios::sync_with_stdio(false);//cin.tie(0);//cout.tie(0);scanf("%d",&t);while(t--){scanf("%d%d",&n,&k);printf("%d\n",findKthNumber(n,k));}#ifdef DEBUGprintf("Time cost : %lf s\n",(double)clock()/CLOCKS_PER_SEC); #endif//cout << "Hello world!" << endl;return 0; }?
總結
