图片加载可能有点慢,请跳过题面先看题解,谢谢 在切水题的道路上狂奔,一发不可收拾... 这道题好像不用写什么题解吧,吐个槽什么的算了 一眼题,大佬们都不屑于做,只有我这种弱菜才来写这种题目玩儿 记个前缀和,直接二分一个长度, \(XJB\) 搞一下就好了 思考时间: \(1s\) ,代码时间 \(1min\) . //made by Hero_of_Someone #include<iostream> #include<cstdio> #include<cstdlib>…

题目 传送门:QWQ 分析 一开始没看到都是正整数根本不会做...... 看到了就是水题了.(但还是sb WA了一发) 尺取法搞一搞 代码 #include <bits/stdc++.h> using namespace std; + ; int A[maxn], B[maxn]; int main(){ int n,s; ){ ;i<=n;i++) scanf("%d",&A[i]); B[]=; ;i<=n;i++) B[i]=B[i-]+A[i];…

题目链接:https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=679 解题报告:给定一个正整数的序列,和一个S,求长度最短的子序列,使它们的和大于或等于S.序列长度n <= 100000 很明显,如果枚举起点和终点的话,时间复杂度是O(n^3),不行.怎么能在O(1)时间求出一个子序列的和是多少呢,可以用另一个数组sum[i…

有一个正整数序列,求最短的子序列使得其和大于等于S,并输出最短的长度. 用数组b[i]存放序列的前i项和,所以b[i]是递增的. 遍历终点j,然后在区间[0, j)里二分查找满足b[j]-b[i]≥S的最大的i,时间复杂度为O(nlongn). 这里二分查找用到库函数lower_bound() //#define LOCAL #include <iostream> #include <cstdio> #include <cstring> #include <alg…

input n s 10<=n<=100000,s<1e9 a1 a2 ... an  ai<=10000 output 大于s的最短子序列和的长度,没有输出0 #include <cstdio> #include <queue> #include <cstring> #include <iostream> #include <cstdlib> #include <algorithm> #include <…

题意:求最小的长度L满足该长度上的元素和大于等于S 最近dp做多了总有一种能用dp解决一切的错觉 二分长度解决 #include<iostream> #include<algorithm> #include<cstdio> #include<cstring> #include<cstdlib> #include<cmath> #include<string> #include<vector> #include&…

看到限时3S,自己写了一个二重循环的,然后华丽的 TLE...T T 瞄了瞄书上,作者的思路果然是很好.膜拜中. 他只枚举了终点,然后用二分查找. 用到了lower_bound函数,这个lower_bound(first,last,val)在first和last中的前闭后开区间进行二分查找,返回大于或等于val的第一个元素位置.如果所有元素都小于val,则返回last的位置. 简单的说,就是当val存在时,返回它出现的第一个位置.如果不存在,就返回一个这样的下标i,在此处插入val(原来的元素s…

题意很简单,在一串正整数序列中找一个连续的子序列使该序列和大于等于一个已知量S,但要求序列长度最短,通常喜欢暴力枚举 这个题目跟大白书之前的一个题目很像,在数列A中 求 Ai-Aj最大 并且 i<J;这个题目巧妙一点,就直接只枚举j,然后在枚举j的过程中不断更新j前面的最大值即为Ai,即可只用O(n)的复杂度 同样,本题也是,先预处理下,把每个数的前缀和B求出来,这样求某一子序列 只要知道起终点,直接用B[J]-B[i]即可,只是枚举子序列的终点j,初始起点设置为i=0,如果满足B[j]-B[i…

A sequence of numbers is called arithmetic if it consists of at least three elements and if the difference between any two consecutive elements is the same. For example, these are arithmetic sequences: 1, 3, 5, 7, 9 7, 7, 7, 7 3, -1, -5, -9 The follo…

Given a string s and a string t, check if s is subsequence of t. You may assume that there is only lower case English letters in both s and t. t is potentially a very long (length ~= 500,000) string, and s is a short string (<=100). A subsequence of…

A sequence of numbers is called a wiggle sequence if the differences between successive numbers strictly alternate between positive and negative. The first difference (if one exists) may be either positive or negative. A sequence with fewer than two…

Given an unsorted array return whether an increasing subsequence of length 3 exists or not in the array. Formally the function should: Return true if there exists i, j, k such that arr[i] < arr[j] < arr[k] given 0 ≤ i < j < k ≤ n-1 else return…

Given an unsorted array of integers, find the length of longest increasing subsequence. For example, Given [10, 9, 2, 5, 3, 7, 101, 18], The longest increasing subsequence is [2, 3, 7, 101], therefore the length is 4. Note that there may be more than…

1. 问题描述 子串应该比较好理解,至于什么是子序列,这里给出一个例子:有两个母串 cnblogs belong 比如序列bo, bg, lg在母串cnblogs与belong中都出现过并且出现顺序与母串保持一致,我们将其称为公共子序列.最长公共子序列(Longest Common Subsequence, LCS),顾名思义,是指在所有的子序列中最长的那一个.子串是要求更严格的一种子序列,要求在母串中连续地出现.在上述例子的中,最长公共子序列为blog(cnblogs, belong),最长公…

1. Description Given an unsorted array return whether an increasing subsequence of length 3 exists or not in the array. Formally the function should: Return true if there exists i, j, k such that arr[i] < arr[j] < arr[k] given 0 ≤ i < j < k ≤…

D. Dense Subsequence time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output You are given a string s, consisting of lowercase English letters, and the integer m. One should choose some symbols fr…

UVA - 11404 Palindromic Subsequence 题意:一个字符串,删去0个或多个字符,输出字典序最小且最长的回文字符串 不要求路径区间DP都可以做 然而要字典序最小 倒过来求LCS,转移同时维护f[i][j].s为当前状态字典序最小最优解 f[n][n].s的前半部分一定是回文串的前半部分(想想就行了) 当s的长度为奇时要多输出一个(因为这样长度+1,并且字典序保证最小(如axyzb  bzyxa,就是axb|||不全是回文串的原因是后半部分的字典序回文串可能不是最小,多…

UVALive - 4108 SKYLINE Time Limit: 3000MS     64bit IO Format: %lld & %llu Submit Status uDebug Description   The skyline of Singapore as viewed from the Marina Promenade (shown on the left) is one of the iconic scenes of Singapore. Country X would a…

UVALive - 3942 Remember the Word A potentiometer, or potmeter for short, is an electronic device with a variable electric resistance. It has two terminals and some kind of control mechanism (often a dial, a wheel or a slide) with which the resistance…

UVALive - 3942 Remember the Word Neal is very curious about combinatorial problems, and now here comes a problem about words. Know- ing that Ray has a photographic memory and this may not trouble him, Neal gives it to Jiejie. Since Jiejie can’t remem…

Longest Increasing Subsequence(LIS) 一个美丽的名字 非常经典的线性结构dp [朴素]:O(n^2) d(i)=max{0,d(j) :j<i&&a[j]<a[i]}+1 直接两个for [二分查找优化]:O(n^2) g(i):d值为i的最小的a  每次更新然后lower_bound即可 ［大于等于］ lower_boundReturn iterator to lower bound Returns an iterator pointing…

Given a sequence of integers, find the longest increasing subsequence (LIS). You code should return the length of the LIS. Have you met this question in a real interview?     Example For [5, 4, 1, 2, 3], the LIS  is [1, 2, 3], return 3 For [4, 2, 4,…

Given a sequence of integers, find the longest increasing subsequence (LIS). You code should return the length of the LIS. Example For [5, 4, 1, 2, 3], the LIS  is [1, 2, 3], return 3 For [4, 2, 4, 5, 3, 7], the LIS is [4, 4, 5, 7], return 4 Challeng…

传送门:D Dense Subsequence 题意:输入一个m,然后输入一个字符串,从字符串中取出一些字符组成一个串,要求满足:在任意长度为m的区间内都至少有一个字符被取到,找出所有可能性中字典序最小的情况,并按字典序输出 思路:字典序 例如 aaaaaaab < ab  也就是说,如果满足要求的取法中取到了b 那么所有的a都应该被取到,这样才可以保证字典序最小,那么也就是说在26个字母中找到一定要被取的最大字母,然后再确定最大的字母的个数,比它小的全部要取 AC代码: #include &quo…

原题链接在这里:http://www.lintcode.com/en/problem/longest-common-subsequence/ 题目: Given two strings, find the longest common subsequence (LCS). Your code should return the length of LCS. Clarification What's the definition of Longest Common Subsequence? htt…

Given a sequence of K integers { N1, N2, ..., NK }. A continuous subsequence is defined to be { Ni, Ni+1, ..., Nj } where 1 <= i <= j <= K. The Maximum Subsequence is the continuous subsequence which has the largest sum of its elements. For examp…

1​​, N2N_2N​2​​, ..., NKN_KN​K​​ }. A continuous subsequence is defined to be { NiN_iN​i​​, Ni+1N_{i+1}N​i+1​​, ..., NjN_jN​j​​ } where 1≤i≤j≤K1 \le i \le j \le K1≤i≤j≤K. The Maximum Subsequence is the continuous subsequence which has the largest sum…

Problem Introduction In this problem, your goal is to compute the length of a longest common subsequence of three sequences. Problem Description Task.Given three sequences \(A=(a_1,a_2,\cdots,a_n)\); \(B = (b_1, b_2,\cdots,b_m)\), and \(C=(c_1,c_2,\c…

最长公共子序列 英文缩写为LCS(Longest Common Subsequence).其定义是,一个序列 S ,如果分别是两个或多个已知序列的子序列,且是所有符合此条件序列中最长的,则 S 称为已知序列的最长公共子序列.而最长公共子串(要求连续)和最长公共子序列是不同的 应用 最长公共子序列是一个十分实用的问题,它可以描述两段文字之间的“相似度”,即它们的雷同程度,从而能够用来辨别抄袭.对一段文字进行修改之后,计算改动前后文字的最长公共子序列,将除此子序列外的部分提取出来,这种方法判断修改的…

本题要求在O(n)时间内求解.用delta储存相邻两个数的差,如果相邻的两个delta不同负号,那么说明子序列摇摆了一次.参看下图的nums的plot.这个例子的答案是7.平的线段部分我们支取最左边的一个点.除了最左边的边界点,我们要求delta != 0, 并且newDelta * delta <= 0.(这里不能只取<号),否则dot 5和7就会被忽略,因为他们的newDelta*delta = 0. def wiggleMaxLength(self, nums): ""…