A. Combination Lock 拨密码..最少次数..密码最多有1000位. 用字符串存起来,然后每位大的减小的和小的+10减大的,再取较小值加起来就可以了... #include<stdio.h> #include<math.h> #include<string.h> #include<iostream> #include<algorithm> #include<map> #include<set> #inclu…

题目传送门 /* 题意:告诉起点终点,踩一次, '.'变成'X',再踩一次,冰块破碎,问是否能使终点冰破碎 DFS:如题解所说,分三种情况:1. 如果两点重合,只要往外走一步再走回来就行了:2. 若两点相邻, 那么要不就是踩一脚就破了或者踩一脚走开再走回来踩一脚破了:3. 普通的搜索看是否能到达, 若能还是要讨论终点踩几脚的问题:) DFS 耗时大,险些超时,可以用BFS来做 */ #include <cstdio> #include <algorithm> #include &l…

题目传送门 /* 贪心:首先要注意,y是中位数的要求:先把其他的都设置为1,那么最多有(n-1)/2个比y小的,cnt记录比y小的个数 num1是输出的1的个数,numy是除此之外的数都为y,此时的numy是最少需要的,这样才可能中位数大于等于y */ #include <cstdio> #include <iostream> #include <algorithm> #include <cstring> using namespace std; ; con…

题目传送门 /* 贪心水题:累加到目标数字的距离,两头找取最小值 */ #include <cstdio> #include <iostream> #include <algorithm> #include <cstring> using namespace std; ; const int INF = 0x3f3f3f3f; char s[MAXN], t[MAXN]; int main(void) //Codeforces Round #301 (Div…

A. Combination Lock time limit per test:2 seconds memory limit per test:256 megabytes input:standard input output:standard output Scrooge McDuck keeps his most treasured savings in a home safe with a combination lock. Each time he wants to put there…

D. Bad Luck Island Time Limit: 1 Sec  Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/540/problem/D Description The Bad Luck Island is inhabited by three kinds of species: r rocks, s scissors and p papers. At some moments of time two random i…

C. Ice Cave Time Limit: 1 Sec  Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/540/problem/C Description You play a computer game. Your character stands on some level of a multilevel ice cave. In order to move on forward, you need to descend…

B. School Marks Time Limit: 1 Sec  Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/540/problem/B Description Little Vova studies programming in an elite school. Vova and his classmates are supposed to write n progress tests, for each test the…

A. Combination Lock Time Limit: 1 Sec  Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/540/problem/A Description Scrooge McDuck keeps his most treasured savings in a home safe with a combination lock. Each time he wants to put there the treas…

题意与分析(CodeForces 540D) 是一道概率dp题. 不过我没把它当dp做... 我就是凭着概率的直觉写的,还好这题不算难. 这题的重点在于考虑概率:他们喜相逢的概率是多少?考虑超几何分布的变形:\[P=\frac{C^1_aC^1_b}{C^2_{a+b+c}-\frac{a(a-1)}{2}-\frac{b(b-1)}{2}-\frac{c(c-1)}{2}}=\frac{ab}{ab+bc+ac}\]即可. 最后还有求和的操作需要注意一下(因为我们没考虑\(i,j,k\)为0的…