题目链接 :http://codeforces.com/contest/816/problem/B 题意 :给出 n 表示区间个数,限定值 k 以及问询次数 q,当一个数被大于或等于 k 个区间重复覆盖时才算有效数,每一次问询都是以区间方式给出,例如(L, R)问你在这个L~R的范围内有多少个数是有效数(即包含这些数的区间个数>=k). 分析 : 这题可以预先统计哪些数被大于或者等于 k 个原始区间重复覆盖,只要提前将这些满足条件的数递增地编上权值构成前缀和序列,然后对于每段问询只要将前缀和序列…

题目链接:http://codeforces.com/contest/816/problem/C 题意 :给出一个 n*m 的变化后的矩阵,变化前矩阵的元素全是0,变化的规则是选择其中的一行或者一列将元素进行加一操作,问你最少用几步操作能将全零的矩阵变成一开始输入的矩阵,如果无法做到则输出-1,否则输出操作的总次数以及具体的操作步骤. 分析 :如果跟着题意顺着想如何从全零矩阵进行变化那可能比较费劲,不如将一开始输入的矩阵进行减的操作(即逆操作)使其最后变成全零矩阵可能会更简单操作,因为只是在原始…

http://codeforces.com/contest/816/problem/B To stay woke and attentive during classes, Karen needs some coffee! Karen, a coffee aficionado, wants to know the optimal temperature for brewing the perfect cup of coffee. Indeed, she has spent some time r…

To stay woke and attentive during classes, Karen needs some coffee! Karen, a coffee aficionado, wants to know the optimal temperature for brewing the perfect cup of coffee. Indeed, she has spent some time reading several recipe books, including the u…

To stay woke and attentive during classes, Karen needs some coffee! Karen, a coffee aficionado, wants to know the optimal temperature for brewing the perfect cup of coffee. Indeed, she has spent some time reading several recipe books, including the u…

CodeForces 816B Karen and Coffee(前缀和,大量查询) Description Karen, a coffee aficionado, wants to know the optimal temperature for brewing the perfect cup of coffee. Indeed, she has spent some time reading several recipe books, including the universally ac…

To stay woke and attentive during classes, Karen needs some coffee! Karen, a coffee aficionado, wants to know the optimal temperature for brewing the perfect cup of coffee. Indeed, she has spent some time reading several recipe books, including the u…

B. Karen and Coffee time limit per test 2.5 seconds memory limit per test 512 megabytes input standard input output standard output To stay woke and attentive during classes, Karen needs some coffee! Karen, a coffee aficionado, wants to know the opti…

To stay woke and attentive during classes, Karen needs some coffee! Karen, a coffee aficionado, wants to know the optimal temperature for brewing the perfect cup of coffee. Indeed, she has spent some time reading several recipe books, including the u…

B. Karen and Coffee time limit per test 2.5 seconds memory limit per test 512 megabytes input standard input output standard output To stay woke and attentive during classes, Karen needs some coffee! Karen, a coffee aficionado, wants to know the opti…