DZY has a sequence a, consisting of n integers. We'll call a sequence ai, ai + 1, ..., aj (1 ≤ i ≤ j ≤ n) a subsegment of the sequence a. The value (j - i + 1) denotes the length of the subsegment. Your task is to find the longest subsegment of a, su…

A. DZY Loves Sequences time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output DZY has a sequence a, consisting of n integers. We'll call a sequence ai, ai + 1, ..., aj (1 ≤ i ≤ j ≤ n) a subsegment…

题目地址:http://codeforces.com/contest/447/problem/C C. DZY Loves Sequences time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output DZY has a sequence a, consisting of n integers. We'll call a sequence…

题意:给出一列数,在这个序列里面找到一个连续的严格上升的子串,现在可以任意修改序列里面的一个数,问得到的子串最长是多少 看的题解,自己没有想出来 假设修改的是a[i],那么有三种情况, 1.a[i]>a[i-1],那么求出向左能够延伸的最长的长度 2.a[i]<a[i-1],那么求出向右能够延伸的最长的长度 3.如果修改的这个数刚好夹在两个数的中间,这种情况比上面两种都优, 即为a[i-1]<a[i+1]-1,求出左右能够延伸的最长的长度 然后因为a[i]本身还没有算进去,所以求出最大值…

<题目链接> 题目大意: 给定一个长度为$n$的序列,现在最多能够改变其中的一个数字,使其变成任意值.问你这个序列的最长严格上升子段的长度是多少. #include <bits/stdc++.h> using namespace std; ; int a[N],suf[N],pre[N]; int main(){ ;cin>>n; ;i<=n;++i) scanf(]=1e9+; ;i<=n;++i) { ]) pre[i]=pre[i-]+;; ans=m…

题意:给定一个序列a,求最长的连续子序列b的长度,在至多修改b内一个数字(可修改为任何数字)的条件下,使得b严格递增. 分析: 1.因为至多修改一个数字,假设修改a[i], 2.若能使a[i] < a[i + 1] 且 a[i] > a[i - 1],则修改a[i]能得到的最长连续子序列长度为l[i - 1] + r[i + 1] + 1. 3.若不满足条件2,则修改a[i]能得到的最长连续子序列长度应取l[i - 1] + 1(即从a[i-1]能向左延伸的最大长度加上a[i]形成的序列)和r…

题目传送门 /* DP:先用l,r数组记录前缀后缀上升长度,最大值会在三种情况中产生: 1. a[i-1] + 1 < a[i+1],可以改a[i],那么值为l[i-1] + r[i+1] + 1 2. l[i-1] + 1 3. r[i+1] + 1 //修改a[i] */ #include <cstdio> #include <algorithm> #include <cstring> using namespace std; ; const int INF…

预处理出每一个数字能够向后延伸多少,然后尝试将两段拼起来. C. DZY Loves Sequences time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output DZY has a sequence a, consisting of n integers. We'll call a sequence ai, ai + 1, ..., a…

447C - DZY Loves Sequences 思路:dp 代码: #include<bits/stdc++.h> using namespace std; #define ll long long const int INF=0x3f3f3f3f; ; int a[N]; int f[N],g[N]; int main() { ios::sync_with_stdio(false); cin.tie(); int n; cin>>n; f[]=; cin>>a[…

C. DZY Loves Sequences time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output DZY has a sequence a, consisting of n integers. We'll call a sequence ai, ai + 1, ..., aj (1 ≤ i ≤ j ≤ n) a subsegment…