time limit per test4 seconds memory limit per test512 megabytes inputstandard input outputstandard output Vanya got bored and he painted n distinct points on the plane. After that he connected all the points pairwise and saw that as a result many tri…

题目链接 可以发现 十进制4 对应 二进制100 十进制16 对应 二进制10000 十进制64 对应 二进制1000000 可以发现每多两个零,4的次幂就增加1. 用string读入题目给定的二进制数字,求出其长len,当len为奇数时,第一位为1,后面的位数如果都为0,则输出len,如果有一个不为0,则输出len+1: 当len为偶数时,则输出len.(之所以这样输出是因为题目给定4的次幂是从0开始的) #include<iostream> #include<string> #…

题意:给出n个不同的点,问能组成多少个不同的三角形 题解:对于每个点对,我们生成一个直线,用a*x+b=y表示,用map记录ab,这样就确定了一个直线,这样我们就能算出有多少点是共线的,这样复杂度就是O(N*N*lgN) 虽然这个题目n的三次方也可以过…

time limit per test1 second memory limit per test256 megabytes inputstandard input outputstandard output Pasha decided to invite his friends to a tea party. For that occasion, he has a large teapot with the capacity of w milliliters and 2n tea cups,…

time limit per test2 seconds memory limit per test256 megabytes inputstandard input outputstandard output Kevin has just recevied his disappointing results on the USA Identification of Cows Olympiad (USAICO) in the form of a binary string of length n…

time limit per test4 seconds memory limit per test256 megabytes inputstandard input outputstandard output Peppa the Pig was walking and walked into the forest. What a strange coincidence! The forest has the shape of a rectangle, consisting of n rows…

time limit per test1 second memory limit per test256 megabytes inputstandard input outputstandard output Vanya got an important task - he should enumerate books in the library and label each book with its number. Each of the n books should be assigne…

time limit per test1 second memory limit per test256 megabytes inputstandard input outputstandard output Anton loves transforming one permutation into another one by swapping elements for money, and Ira doesn't like paying for stupid games. Help them…

time limit per test1 second memory limit per test256 megabytes inputstandard input outputstandard output The mobile application store has a new game called "Subway Roller". The protagonist of the game Philip is located in one end of the tunnel a…

time limit per test2 seconds memory limit per test256 megabytes inputstandard input outputstandard output There are n beacons located at distinct positions on a number line. The i-th beacon has position ai and power level bi. When the i-th beacon is…

time limit per test1 second memory limit per test256 megabytes inputstandard input outputstandard output The process of mammoth's genome decoding in Berland comes to its end! One of the few remaining tasks is to restore unrecognized nucleotides in a…

[题目链接]:http://codeforces.com/contest/510/problem/C [题意] 给你n个字符串; 问你要怎么修改字典序; (即原本是a,b,c..z现在你可以修改每个字母在字典序中的位置了); 才能使得这n个字符串是字典序升序的; [题解] 对于第i个字符串; 让他和第i+1..n个字符串比较->j; 找到第一个不同的位置pos; 然后 必然是要 s[i][pos]< s[j][pos]的: 拓扑排序! 即s[i][pos]建一条边指向s[j][pos] 然后做…

[题目链接]:http://codeforces.com/contest/807/problem/D [题意] 给出n个人的比赛信息; 5道题 每道题,或是没被解决->用-1表示; 或者给出解题的所用的时间; (每道题的分数与解决率有关,越高,分越低); 然后有个人想利用这个特点,注册很多个账号; 试图改变每道题的解决率,以期让自己的分数大于某个人; 如果这个人没有解决某道题的话; 那些新加入的人也不能解决那道题. 问最少需要注册多少个账号才能让你的分数大于某个人; [题解] 顺序枚举加入了多少…

[题目链接]:http://codeforces.com/contest/807/problem/B [题意] 你在另外一场已经结束的比赛中有一个排名p; 然后你现在在进行另外一场比赛 然后你当前有一个分数x; 以及另外一个分数y,表示如果要拿第一需要的分数; 你可以通过hack使得分数x大于分数y; 然后你最后的分数x会决定你那个排名p能不能在已经结束的那场比赛中拿到奖品; 问你技能拿到奖品,又能在这场比赛中夺冠;至少需要hack成功多少次(失败的不需要输出); (hack规则和cf的一样)…

time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output People do many crazy things to stand out in a crowd. Some of them dance, some learn by heart rules of Russian language, some try to become a…

time limit per test2 seconds memory limit per test256 megabytes inputstandard input outputstandard output Generous sponsors of the olympiad in which Chloe and Vladik took part allowed all the participants to choose a prize for them on their own. Chri…

time limit per test1 second memory limit per test256 megabytes inputstandard input outputstandard output Vanya is doing his maths homework. He has an expression of form , where x1, x2, -, xn are digits from 1 to 9, and sign represents either a plus '…

time limit per test4 seconds memory limit per test256 megabytes inputstandard input outputstandard output All our characters have hobbies. The same is true for Fedor. He enjoys shopping in the neighboring supermarket. The goods in the supermarket hav…

time limit per test1 second memory limit per test256 megabytes inputstandard input outputstandard output On the Literature lesson Sergei noticed an awful injustice, it seems that some students are asked more often than others. Seating in the class lo…

time limit per test1 second memory limit per test256 megabytes inputstandard input outputstandard output As behooves any intelligent schoolboy, Kevin Sun is studying psycowlogy, cowculus, and cryptcowgraphy at the Bovinia State University (BGU) under…

time limit per test2 seconds memory limit per test256 megabytes inputstandard input outputstandard output Mr. Funt now lives in a country with a very specific tax laws. The total income of mr. Funt during this year is equal to n (n ≥ 2) burles and th…

[codeforces 415D]Mashmokh and ACM 题意:美丽数列定义:对于数列中的每一个i都满足:arr[i+1]%arr[i]==0 输入n,k(1<=n,k<=2000),问满足[数列长度是k && 数列中每一个元素arr[i]在1~n之间 && 数列中元素可以重复]的数列有多少个?结果对10^9+7取余 解题思路:dp[i][j]表示长度是j,最后一位是i的种数 if(kk%i==0) dp[kk][j+1]+=dp[i][j] #inc…

题目链接: http://codeforces.com/problemset/problem/691/D 题目大意: 给一个1到N的排列,M个操作(1<=N,M<=106),每个操作可以交换X Y位置上的数字,求可以得到的最大字典序的数列. 题目思路: [搜索][并查集] 这题可以用搜索或者并查集写,都能过. 把位置分成若干块,每一块里面的位置都是可以被这一块里另一个位置经过若干次调换的(类似强连通,位置可达). 然后把每一块位置里的 位置按从小到大排序,位置上的值按从大到小排序,依次填入位置…

题目链接: http://codeforces.com/gym/100526 http://acm.hunnu.edu.cn/online/?action=problem&type=show&id=11674&courseid=0 题目大意: N个学生M道题(1<=N<=12,1<=M<=30),每道题只有正误两种选项(0 1),每个学生的答题情况和正确题数已知,求标准答案可能有多少种. 如果标准答案只有一种则输出标准答案,否则输出解的个数. 题目思路: […

题目链接: http://codeforces.com/problemset/problem/706/E 题目大意: 给一个N*M的矩阵,Q个操作,每次把两个同样大小的子矩阵交换,子矩阵左上角坐标分别为(a,b)和(c,d),高度h,宽度w. (2 ≤ n, m ≤ 1000, 1 ≤ q ≤ 10 000) 题目思路: [链表][模拟] 这一看如果直接模拟的话时间复杂度是N*M*Q,肯定T了. 把矩阵看成链表,链表的方向有上下左右四种,其实每次交换两个子矩阵只改变的外围一圈的链表值,而内部的链…

题目链接: http://codeforces.com/problemset/problem/710/D 题目大意: 两个等差数列a1x+b1和a2x+b2,求L到R区间内重叠的点有几个. 0 < a1, a2 ≤ 2·109,  - 2·109 ≤ b1, b2, L, R ≤ 2·109, L ≤ R). 题目思路: [数论][扩展欧几里得] 据题意可得同余方程组 x=b1(mod a1) 即 x=k1*a1+b1 x=b2(mod a2) x=k2*a2+b2 化简,k1*a1=k2*a2…

题目链接: http://codeforces.com/problemset/problem/710/E 题目大意: 问写N个字符的最小花费,写一个字符或者删除一个字符花费A,将当前的字符数量翻倍花费B. 题目思路: [动态规划][最短路] [动态规划]: 如果当前x不是2的倍数,那么一定需要单个字符增加或删除,而这个单个操作越靠后答案越优. dp(x)=a+min(dp(x-1),dp(x+1)) 如果当前x是2的倍数,那么有两种情况,一种是通过翻倍的方式获得,一种是通过累加的方式获得.只要比…

题目链接: http://codeforces.com/problemset/problem/707/D 题目大意: 一个N*M的书架,支持4种操作 1.把(x,y)变为有书. 2.把(x,y)变为没书. 3.把x行上的所有书状态改变,有变没,没变有. 4.回到第K个操作时的状态. 求每一次操作后书架上总共多少书. 题目思路: [离线][深搜][树] 现场有思路不过没敢写哈.还是太弱了. 总共只用保存一张图,把操作看成一棵树,一开始I操作连接在I-1操作后,如果遇到操作4的话,把I操作与I-1操…

题目链接: http://codeforces.com/problemset/problem/698/B http://codeforces.com/problemset/problem/699/D 题目大意: 通过给定当前节点的父亲给你一棵有错的树,可能有多个根和环,输出改成正确的一棵树至少要修改几个节点的父亲和修改后所有点的父亲值 题目思路: [并查集][模拟] 用并查集把成环的归在一起(类似强连通分量),然后统计分量数并修改. 第一个出现的当作根,其余的每一块连通分量都去掉一条边改为连接到…

题目链接: http://codeforces.com/problemset/problem/696/A 题目大意: 一个满二叉树,深度无限,节点顺序编号,k的儿子是k+k和k+k+1,一开始树上的边权都为0 N(N<=1000)个操作,操作两种,1是从u到v的路径上的所有边权+w,2是求u到v的边权和.(1 ≤ v, u ≤ 1018, v ≠ u, 1 ≤ w ≤ 109) 题目思路: [STL][模拟] 用map写很快,第一次用很生疏.现学只看了一点点. 因为是满二叉树所以直接暴力求LCA…