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You are given n points on Cartesian plane. Every point is a lattice point (i. e. both of its coordinates are integers), and all points are distinct. You may draw two straight lines (not necessarily d...

Ivan has an array consisting of n different integers. He decided to reorder all elements in increasing order. Ivan loves merge sort so he decided to represent his array with one or several increasing ...

You are given a tree consisting exactly of 

Vasya is preparing a contest, and now he has written a statement for an easy problem. The statement is a string of length 

You are given a bracket sequence 

C. Multiplicity time limit per test 3 seconds memory limit per test 256 megabytes input standard input output standard output You are given an integer array 

题目链接 题意： 给出一个ａ数组，让你构建ｂ数组，要求满足下列条件： b1=0; for every pair of indices i and j such that 1≤i,j≤n, if ai=aj, then bi=bj (note that if ai≠aj, it is still possible that bi=bj); for every index i∈[1,n−1] ei...

Little Paul wants to learn how to play piano. He already has a melody he wants to start with. For simplicity he represented this melody as a sequence a1,a2,…,ana1,a2,…,an of key numbers: the more a nu...

You are given a string s consisting of exactly n characters, and each character is either ‘0’, ‘1’ or ‘2’. Such strings are called ternary strings. Your task is to replace minimum number of characters...