Codeforces Round #333 (Div. 2) B. Approximating a Constant Range
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发布时间：2019-06-28
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B. Approximating a Constant Range
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output
When Xellos was doing a practice course in university, he once had to measure the intensity of an effect that slowly approached equilibrium. A good way to determine the equilibrium intensity would be choosing a sufficiently large number of consecutive data points that seems as constant as possible and taking their average. Of course, with the usual sizes of data, it's nothing challenging — but why not make a similar programming contest problem while we're at it?
You're given a sequence of n data points a1, ..., an. There aren't any big jumps between consecutive data points — for each 1 ≤ i < n, it's guaranteed that |ai + 1 - ai| ≤ 1.
A range [l, r] of data points is said to be almost constant if the difference between the largest and the smallest value in that range is at most 1. Formally, let M be the maximum and m the minimum value of ai for l ≤ i ≤ r; the range [l, r] is almost constant if M - m ≤ 1.
Find the length of the longest almost constant range.
Input
The first line of the input contains a single integer n (2 ≤ n ≤ 100 000) — the number of data points.
The second line contains n integers a1, a2, ..., an (1 ≤ ai ≤ 100 000).
Output
Print a single number — the maximum length of an almost constant range of the given sequence.
Sample test(s)
input
51 2 3 3 2
output
4
input
115 4 5 5 6 7 8 8 8 7 6
output
5
Note
In the first sample, the longest almost constant range is [2, 5]; its length (the number of data points in it) is 4.
In the second sample, there are three almost constant ranges of length 4: [1, 4], [6, 9] and [7, 10]; the only almost constant range of the maximum length 5 is [6, 10].
题目大意：
给你一串数，让你求最大的区间（最大值-最小值<=1）
解题思路：
我是用集合做的。。。
#include #include #include #include #include #include #include #include #include using namespace std;#define MM(a) memset(a,0,sizeof(a))typedef long long LL;typedef unsigned long long ULL;const int maxn = 1e5+5;const int mod = 1e9+7;const double eps = 1e-10;const int INF = 0x3f3f3f3f;LL gcd(LL a, LL b){ if(b == 0) return a; return gcd(b, a%b);}multiset s;int arr[maxn];int main(){ int n; while(cin>>n) { s.clear(); for(int i=0; i 1) { s.erase(s.find(arr[i])); i++; } ret = max(ret, int(s.size())); j++; } cout< <