C. Beautiful Numbers 题目连接: http://www.codeforces.com/contest/300/problem/C Description Vitaly is a very weird man. He's got two favorite digits a and b. Vitaly calls a positive integer good, if the decimal representation of this integer only contains…

链接: https://codeforces.com/contest/1265/problem/B 题意: You are given a permutation p=[p1,p2,-,pn] of integers from 1 to n. Let's call the number m (1≤m≤n) beautiful, if there exists two indices l,r (1≤l≤r≤n), such that the numbers [pl,pl+1,-,pr] is a…

题目链接:https://codeforces.com/contest/1265/problem/B 题意 给出大小为 $n$ 的一个排列,问对于每个 $i(1 \le i \le n)$,原排列中是否有一个大小为 $i$ 的连续子排列. 题解 从小到大构造排列,记录当前排列中数的最小下标和最大下标,若最小下标和最大下标的间距刚好为排列的长度,则说明大小为 $i$ 的排列是连续的. 代码一 #include <bits/stdc++.h> using namespace std; void s…

https://codeforces.com/contest/1139/problem/C 题意 一颗有n个点的树,需要挑选出k个点组成序列(可重复),按照序列的顺序遍历树,假如经过黑色的边,那么这个序列就是好的,问有多少个好的序列 题解 黑边不连,红边连,假如两个点不在同一并查集,那么一定经过黑边 定义\(dp[i][j][k]\)为选择前i个点,起始点为j,是否已经经过黑边(k)的方案数 \(dp[i-1][j][0]*(n-N[fin(j)])+dp[i-1][j][1]*n - > dp…

#include<bits/stdc++.h>using namespace std;typedef struct{ double k,b;}node;node k[1000007];bool cmp(node&a,node&b){ if(a.k==b.k)  return a.b<b.b; return a.k<b.k;}long long x[1007],y[1007];int main(){ long long n,ans=0,tot=0; scanf(&qu…

题目传送门 /* 构造:结构体排个序,写的有些啰嗦,主要想用用流,少些了判断条件WA好几次:( */ #include <cstdio> #include <algorithm> #include <cstring> #include <cmath> #include <vector> #include <map> #include <iostream> #include <string> using name…

A. Array 模拟. B. Coach 模拟. C. Beautiful Numbers good number的位和最大不超过\(10^7\),那么只要枚举a或b的个数,然后最多循环7次判断位和是否是good number. D. Painting Square 因为新划分的4个小矩形也需要为正方形,所以当前长度n必须为奇数,否则无法继续划分. \(f(i,j)\)表示长为\(2^i-1\),操作\(j\)次的方案数. 直接分成4部分比较难,所以可以先考虑分成左右两部分,左右两部分继续考虑…

链接: https://codeforces.com/contest/1265/problem/D 题意: An integer sequence is called beautiful if the difference between any two consecutive numbers is equal to 1. More formally, a sequence s1,s2,-,sn is beautiful if |si−si+1|=1 for all 1≤i≤n−1. Trans…

链接: https://codeforces.com/contest/1265/problem/C 题意: So the Beautiful Regional Contest (BeRC) has come to an end! n students took part in the contest. The final standings are already known: the participant in the i-th place solved pi problems. Since…

B. Coach 题目连接: http://www.codeforces.com/contest/300/problem/A Description A programming coach has n students to teach. We know that n is divisible by 3. Let's assume that all students are numbered from 1 to n, inclusive. Before the university progra…