题意:求$K$的倍数中数位和的最小值. 一开始有一种思路:由于产生答案的数字可能非常大,不便枚举,考虑转化为构造一个数字可以有$x\mod k=0$.然后二分答案数位和,数位DP检验是否存在,但是由于数位DP还是局限于有限大小的数字,所以并不可行.````` 套路见少了.实际上,这种构造数字满足某些条件的,一定可以把目标数字看成是一位一位写下来的,比如$114514$,可以看成逐步写下$1,1,4,5,1,4$不断$\times 10$做加法的结果.所以考虑设$dis_i$为所有$x\mod k…

水过前三道题之后,一直在写这个题,做不对.总有那么几组数据过不去... 看了看题解是最短路,这思路感觉很神奇.看了下唯一做出来这题的那人的代码,是搜索做的. 标程: 对每个数字x,向x+1建一条花费为1的边,向x * 10建一条花费为0的边,这样1---0的最短路+1就是结果了. 可能有人会疑惑9+1=10,费用确是+1这里,因为1 * 10=10已经向10建立了一条更短的边了,9+1=10那条边就不会走了. 看看代码就懂了. #include <bits/stdc++.h> using na…

题目描述 Farmer John has recently purchased a new car online, but in his haste he accidentally clicked the "Submit" button twice when selecting extra features for the car, and as a result the car ended up equipped with two GPS navigation systems! Ev…

Description Berland has n cities, the capital is located in city s, and the historic home town of the President is in city t (s ≠ t). The cities are connected by one-way roads, the travel time for each of the road is a positive integer. Once a year t…

http://acm.hdu.edu.cn/showproblem.php?pid=4960 2014 Multi-University Training Contest 9 Another OCD Patient Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 181    Accepted Submission(s): 58 Pr…

CF449B CF450D http://codeforces.com/contest/450/problem/D http://codeforces.com/contest/449/problem/B Codeforces Round #257 (Div. 2) D Codeforces Round #257 (Div. 1) B D. Jzzhu and Cities time limit per test 2 seconds memory limit per test 256 megaby…

Sparse Graph Problem Description   In graph theory, the complement of a graph G is a graph H on the same vertices such that two distinct vertices of H are adjacent if and only if they are notadjacent in G. Now you are given an undirected graph G of N…

题目链接: Meeting Time Limit: 12000/6000 MS (Java/Others)    Memory Limit: 262144/262144 K (Java/Others)Total Submission(s): 2024    Accepted Submission(s): 628 Problem Description Bessie and her friend Elsie decide to have a meeting. However, after Farm…

Meeting Time Limit: 12000/6000 MS (Java/Others)    Memory Limit: 262144/262144 K (Java/Others) Total Submission(s): 1358    Accepted Submission(s): 435 Problem Description Bessie and her friend Elsie decide to have a meeting. However, after Farmer Jo…

I am going to my home. There are many cities and many bi-directional roads between them. The cities are numbered from 0 to n-1 and each road has a cost. There are m roads. You are given the number of my city t where I belong. Now from each city you h…