题目大意: 求区间 \([x,y]\) 范围内有多少数的二进制表示中的'0'的个数 \(\ge\) '1'的个数. 解题思路: 使用 数位DP 解决这个问题. 我们设状态 f[pos][num0][num1][all0] 表示在: 当前所在数位为 pos : 当前选择的'0'的个数为 num0: 当前选择的'1'的个数为 num1: 到当前位位置是不是前面的数都是前导零(如果都是前导0则 all0==true,否则 all==false). 下的方案数. 我们开函数 dfs(int pos, i…

题目传送门 Round Numbers Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 16439   Accepted: 6776 Description The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (also known as 'Rock, Paper, Scis…

题目链接 POJ3252 题解 为什么每次写出数位dp都如此兴奋? 因为数位dp太苟了 因为我太弱了 设\(f[i][0|1][cnt1][cnt0]\)表示到二进制第\(i\)位,之前是否达到上界,前面已经有\(cnt1\)个\(1\),\(cnt0\)个\(0\)时的方案数 显然当\(cnt1 = 0\)时就不存在任何前导数字了 然后就记忆化搜索 分类讨论各种转移 [为什么我写得好麻烦QAQ是不是我姿势不对] #include<iostream> #include<cstdio>…

题意:给定区间[l,r],l < r ,求区间中满足条件的正整数的个数:二进制表示下0的个数不少于1的个数. 分析:f(x)表示<=x时满足条件的数的个数,所求问题即为f(r)-f(l-1).x二进制表示下从高到低位为1,bi,bi-1, bi-2, b0, 长度为len, 那么f(x)可以这样求解: dp[i][j]表示从i~0位可以任意为0或1时,0的个数比1多j个情况,由于j可能为负数,所以这里方便处理,将j = 40表示0的个数和1的个数一样多. 转移:dp[i][j] = sum{d…

[POJ3252]Round Numbers 试题描述 The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (also known as 'Rock, Paper, Scissors', 'Ro, Sham, Bo', and a host of other names) in order to make arbitrary decisions s…

题目链接:http://poj.org/problem?id=3252 Round Numbers Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 14640   Accepted: 5881 Description The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (al…

Description The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (also known as 'Rock, Paper, Scissors', 'Ro, Sham, Bo', and a host of other names) in order to make arbitrary decisions such as who gets…

D. Roman and Numbers time limit per test 4 seconds memory limit per test 512 megabytes input standard input output standard output Roman is a young mathematician, very famous in Uzhland. Unfortunately, Sereja doesn't think so. To make Sereja change h…

题目链接:https://codeforces.com/contest/55/problem/D 题目大意:给你一段区间[l,r],要求这段区间中可以整除自己每一位(除0意外)上的数字的整数个数,例如15,因为15既可以整除1也可以整除5,所以15符合要求. (1 ≤ li ≤ ri ≤ 9 ·1018). Examples input Copy 11 9 output Copy 9 input Copy 112 15 output Copy 2 解题思路:很明显的数位dp,首先我们可以想一个数…

Round Numbers Time Limit: 2000MS   Memory Limit: 65536K Total Submissions: 7625   Accepted: 2625 Description The cows, as you know, have no fingers or thumbs and thus are unable to play Scissors, Paper, Stone' (also known as 'Rock, Paper, Scissors',…