11D_Beyonder's Blog

CF13959C - From Educational Codeforces Round 88 (Rated for Div. 2) There are two infinite sources of water: hot water of temperature h; cold water of temperature c (c<h). You perform the following procedure of alternating moves: take one cup of the hot water and pour it into an infinitely deep barrel; take one cup of the cold water and pour it into an infinitely deep barrel; take one cup of the hot water … and so on … Note that you always start with the cup of hot water. The barrel is i ...

CF1369C - From Codeforces Round #652 (Div. 2) Lee just became Master in Codeforces, and so, he went out to buy some gifts for his friends. He bought n integers, now it’s time to distribute them between his friends rationally… Lee has nnn integers a1,a2,…,ana_1,a_2,…,a_na1​,a2​,…,an​ in his backpack and he has kkk friends. Lee would like to distribute all integers in his backpack between his friends, such that the iii-th friend will get exactly wiw_iwi​ integers and each integer will be handed ...

Karl likes Codeforces and subsequences. He wants to find a string of lowercase English letters that contains at least kkk subsequences codeforces. Out of all possible strings, Karl wants to find a shortest one. Formally, a codeforces subsequence of a string sss is a subset of ten characters of sss that read codeforces from left to right. For example, codeforces contains codeforces a single time, while codeforcesisawesome contains codeforces four times: codeforcescisawesome, codeforcecsiscawesome ...

Polycarp found under the Christmas tree an array a of n elements and instructions for playing with it: At first, choose index iii (1≤i≤n)(1≤i≤n)(1≤i≤n) — starting position in the array. Put the chip at the index iii (on the value aia_iai​). While i≤ni≤ni≤n, add aia_iai​ to your score and move the chip aia_iai​ positions to the right (i.e. replace iii with i+aii+a_ii+ai​). If i>ni>ni>n, then Polycarp ends the game. For example, if n=5n=5n=5 and a=[7,3,1,2,3]a=[7,3,1,2,3]a=[7,3,1,2,3], t ...

Problem Description There are nnn columns of blocks standing in a row. The iii-th column has aia_iai​ blocks in the beginning. Each block has size 1×1×11×1×11×1×1. Define (x,y)(x,y)(x,y) represent the block at column xxx and is the yyy-th block from bottom to top. You need to support two operations. 1 x y Push one block to the left, that means you choose one block which has no block at its right and make it move to the left. Because of the friction, the block above it will also move to the left, ...

You are given a string s consisting of lowercase Latin letters “a”, “b” and “c” and question marks “?”. Let the number of question marks in the string sss be kkk. Let’s replace each question mark with one of the letters “a”, “b” and “c”. Here we can obtain all 3k3^k3k possible strings consisting only of letters “a”, “b” and “c”. For example, if s=“ac?b?c” then we can obtain the following strings: [“acabac”, “acabbc”, “acabcc”, “acbbac”, “acbbbc”, “acbbcc”, “accbac”, “accbbc”, “accbcc”]. Your tas ...

Yura has been walking for some time already and is planning to return home. He needs to get home as fast as possible. To do this, Yura can use the instant-movement locations around the city. Let’s represent the city as an area of n×nn×nn×n square blocks. Yura needs to move from the block with coordinates (sx,sy)(s_x,s_y)(sx​,sy​) to the block with coordinates (fx,fy)(f_x,f_y)(fx​,fy​). In one minute Yura can move to any neighboring by side block; in other words, he can move in four directions. A ...

Sometimes it is not easy to come to an agreement in a bargain. Right now Sasha and Vova can’t come to an agreement: Sasha names a price as high as possible, then Vova wants to remove as many digits from the price as possible. In more details, Sasha names some integer price nnn, Vova removes a non-empty substring of (consecutive) digits from the price, the remaining digits close the gap, and the resulting integer is the price. For example, is Sasha names 121312112131211213121, Vova can remove the ...

Portal ↬\looparrowright↬ You are given an integer nnn. You should find a list of pairs (x1,y1),(x2,y2),⋯ ,(xq,yq)(x_1,y_1), (x_2,y_2),\cdots, (x_q,y_q)(x1​,y1​),(x2​,y2​),⋯,(xq​,yq​) (1≤xi,yi≤n1≤x_i,y_i≤n1≤xi​,yi​≤n) satisfying the following condition. Let’s consider some function f:N×N→Nf:\mathbb N\times\mathbb N→\mathbb Nf:N×N→N (we define N\mathbb NN as the set of positive integers). In other words, fff is a function that returns a positive integer for a pair of positive integers. Let’s mak ...

You are given an array aaa consisting of nnn non-negative integers. You have to choose a non-negative integer xxx and form a new array bbb of size nnn according to the following rule: for all iii from 111 to nnn, bi=ai⊕xb_i=a_i⊕xbi​=ai​⊕x (⊕⊕⊕ denotes the operation bitwise XOR). An inversion in the b array is a pair of integers iii and jjj such that 1≤i<j≤n1≤i<j≤n1≤i<j≤n and bi>bjb_i>b_jbi​>bj​. You should choose xxx in such a way that the number of inversions in bbb is minimiz ...