C. The Phone Number time limit per test 1 second memory limit per test 256 megabytes     Mrs. Smith is trying to contact her husband, John Smith, but she forgot the secret phone number! The only thing Mrs. Smith remembered was that any permutation of…

Mrs. Smith is trying to contact her husband, John Smith, but she forgot the secret phone number! The only thing Mrs. Smith remembered was that any permutation of nn can be a secret phone number. Only those permutations that minimize secret value migh…

C. The Phone Number time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Mrs. Smith is trying to contact her husband, John Smith, but she forgot the secret phone number! The only thing Mrs. Smit…

分治,考虑分治到[l,r]的区间(设$mid=(l+r)/2$),将询问分为两类:1.在左/右区间,直接递归下去:2.跨越中间,那么处理出两个数组:L[i][j]表示左区间在开头第i个位置,以数字j为结尾的上升子序列个数(不跨越mid),右区间同理(L和R的计算很简单,只需要再处理出一个L[i][j][k]表示i后面以j为开头,以k为结尾的子序列个数即可)对其求前/后缀和,那么就求出了开头在第i个位置以后/结尾在第i个位置以前的子序列个数设询问区间为[x,y],那么答案就是$\sum_{i=1}…

题目链接: C. Subsequences time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output For the given sequence with n different elements find the number of increasing subsequences with k + 1 elements. It is…

Given a string S and a string T, count the number of distinct subsequences of T in S. A subsequence of a string is a new string which is formed from the original string by deleting some (can be none) of the characters without disturbing the relative…

https://leetcode.com/problems/distinct-subsequences/ Given a string S and a string T, count the number of distinct subsequences of T in S. A subsequence of a string is a new string which is formed from the original string by deleting some (can be non…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=2227 Find the nondecreasing subsequences                                  Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)                                             …

Given a string S and a string T, count the number of distinct subsequences of T in S. A subsequence of a string is a new string which is formed from the original string by deleting some (can be none) of the characters without disturbing the relative…

题目 Given a string S and a string T, count the number of distinct subsequences of T in S. A subsequence of a string is a new string which is formed from the original string by deleting some (can be none) of the characters without disturbing the relati…