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)                                             …

http://acm.hdu.edu.cn/showproblem.php?pid=2227 用dp[i]表示以第i个数为结尾的nondecreasing串有多少个. 那么对于每个a[i] 要去找 <= a[i]的数字那些位置,加上他们的dp值即可. 可以用树状数组维护 #include <cstdio> #include <cstdlib> #include <cstring> #include <cmath> #include <algori…

题目大意:给定一个序列,求出其所有的上升子序列. 题解:一开始我以为是动态规划,后来发现离散后树状数组很好做,首先,c保存的是第i位上升子系列有几个,那么树状数组的sum就直接是现在的答案了,不过更新时不要忘记加1,因为当前元素本身也是一个子序列,比如数列离散后为1 3 2 4 5,那么第一位得到之前的答案为0,更新时1位加1,第二位算出为1,更新时3位加(1+1),第三位也一样,一次类推,同树状数组求逆序对的方法一样,但是更新的不是1,而是之前所有的答案数加1. #include <iostr…

Find the nondecreasing subsequences Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 1235    Accepted Submission(s): 431 Problem Description How many nondecreasing subsequences can you find in…

Problem Description How many nondecreasing subsequences can you find in the sequence S = {s1, s2, s3, ...., sn} ? For example, we assume that S = {1, 2, 3}, and you can find seven nondecreasing subsequences, {1}, {2}, {3}, {1, 2}, {1, 3}, {2, 3}, {1,…

和之前的hdu3030都快一样了 可以参考之前的题解 #include <iostream> #include <cstdio> #include <cstdlib> #include <cstring> #include <algorithm> using namespace std; ; long long n; long long a[maxn]; long long b[maxn]; long long c[maxn]; ; void a…

Find the nondecreasing subsequences Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1072    Accepted Submission(s): 370 Problem Description How many nondecreasing subsequences can you find in t…

Find the nondecreasing subsequences Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1844    Accepted Submission(s): 677 Problem Description How many nondecreasing subsequences can you find in t…

HDU 1000 A + B Problem  I/O HDU 1001 Sum Problem  数学 HDU 1002 A + B Problem II  高精度加法 HDU 1003 Maxsum  贪心 HDU 1004 Let the Balloon Rise  字典树,map HDU 1005 Number Sequence  求数列循环节 HDU 1007 Quoit Design  最近点对 HDU 1008 Elevator  模拟 HDU 1010 Tempter of th…

(一)树状数组的概念 如果给定一个数组,要你求里面所有数的和,一般都会想到累加.但是当那个数组很大的时候,累加就显得太耗时了,时间复杂度为O(n),并且采用累加的方法还有一个局限,那就是,当修改掉数组中的元素后,仍然要你求数组中某段元素的和,就显得麻烦了.所以我们就要用到树状数组,他的时间复杂度为O(lgn),相比之下就快得多.下面就讲一下什么是树状数组: 一般讲到树状数组都会少不了下面这个图: 下面来分析一下上面那个图看能得出什么规律: 据图可知:c1=a1,c2=a1+a2,c3=a3,c4…