A. Lucky Conversion time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Petya loves lucky numbers very much. Everybody knows that lucky numbers are positive integers whose decimal record conta…

Description Petya loves lucky numbers very much. Everybody knows that lucky numbers are positive integers whose decimal record contains only the lucky digits 4 and 7. For example, numbers 47, 744, 4 are lucky and 5, 17, 467 are not. Petya has two str…

Lucky Ticket Time Limit:2000MS     Memory Limit:262144KB     64bit IO Format:%I64d & %I64u Submit Status Practice CodeForces 146A Description Petya loves lucky numbers very much. Everybody knows that lucky numbers are positive integers whose decimal…

题目链接: http://codeforces.com/problemset/problem/353/D?mobile=true H. Queue time limit per test 1 secondmemory limit per test 256 megabytes 问题描述 There are n schoolchildren, boys and girls, lined up in the school canteen in front of the bun stall. The b…

B. Cards time limit per test:2 seconds memory limit per test:256 megabytes input:standard input output:standard output Catherine has a deck of n cards, each of which is either red, green, or blue. As long as there are at least two cards left, she can…

Lucky Sum Time Limit: 2000ms Memory Limit: 262144KB This problem will be judged on CodeForces. Original ID: 121A64-bit integer IO format: %I64d      Java class name: (Any)     Petya loves lucky numbers. Everybody knows that lucky numbers are positive…

I - Parking Lot Time Limit:500MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Submit Status Description To quickly hire highly skilled specialists one of the new IT City companies made an unprecedented move. Every employee was granted a…

C. Lucky Numbers time limit per test 0.5 seconds memory limit per test 64 megabytes input standard input output standard output The numbers of all offices in the new building of the Tax Office of IT City will have lucky numbers. Lucky number is a num…

E. Lucky Queries time limit per test 3 seconds memory limit per test 256 megabytes input standard input output standard output Petya loves lucky numbers very much. Everybody knows that lucky numbers are positive integers whose decimal record contains…

题意: 一个数只含有4,7就是lucky数...现在有一串长度为n的数...问这列数有多少个长度为k子串..这些子串不含两个相同的lucky数... 子串的定义..是从这列数中选出的数..只要序号不同..就不不同的串..如 1 1 的长度为1的子串有两个 题解: 解题前可以先求一下1000000000内有多少个数是lucky的...可以递推的求..也可以暴力求~~可以看出最多1022个lucky数..很少... 现将这堆数的所有lucky数找出来...把相同的放在一个lucky数里计数... d…