Codeforces Round #305 (Div. 1) B. Mike and Feet 单调栈

[b]B. Mike and Feet[/b]

Time Limit: 20 Sec Memory Limit: 256 MB

题目连接

http://codeforces.com/contest/547/problem/B

Description

Mike is the president of country What-The-Fatherland. There are n bears living in this country besides Mike. All of them are standing in a line and they are numbered from 1 to n from left to right. i-th bear is exactly ai feet high.



A group of bears is a non-empty contiguous segment of the line. The size of a group is the number of bears in that group. The strength of a group is the minimum height of the bear in that group.

Mike is a curious to know for each x such that 1 ≤ x ≤ n the maximum strength among all groups of size x.

[b]Input[/b]

The first line of input contains integer n (1 ≤ n ≤ 2 × 105), the number of bears.

The second line contains n integers separated by space, a1, a2, ..., an (1 ≤ ai ≤ 109), heights of bears.

[b]Output[/b]

Print n integers in one line. For each x from 1 to n, print the maximum strength among all groups of size x.

[b]Sample Input[/b]

10
1 2 3 4 5 4 3 2 1 6

Sample Output

6 4 4 3 3 2 2 1 1 1

HINT

[b]题意 [/b]

给你一个堆数，对于（1，n）长度，让你找到线段的最小值的最大值是多少

[b]题解：[/b]

用一个类似单调栈的思想，处理以这个点为最小值可以往左右延伸多少，然后乱搞一下就好了

[b]代码：[/b]

//qscqesze
#include <cstdio>
#include <cmath>
#include <cstring>
#include <ctime>
#include <iostream>
#include <algorithm>
#include <set>
#include <vector>
#include <sstream>
#include <queue>
#include <typeinfo>
#include <fstream>
#include <map>
#include <stack>
typedef long long ll;
using namespace std;
//freopen("D.in","r",stdin);
//freopen("D.out","w",stdout);
#define sspeed ios_base::sync_with_stdio(0);cin.tie(0)
#define test freopen("test.txt","r",stdin)
#define maxn 200001
#define mod 1000000007
#define eps 1e-9
int Num;
char CH[20];
//const int inf=0x7fffffff;   //нчоч╢С
const int inf=0x3f3f3f3f;
inline ll read()
{
ll x=0,f=1;char ch=getchar();
while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
return x*f;
}
inline void P(int x)
{
Num=0;if(!x){putchar('0');puts("");return;}
while(x>0)CH[++Num]=x%10,x/=10;
while(Num)putchar(CH[Num--]+48);
puts("");
}
//**************************************************************************************

int a[maxn];
int dp[maxn];
int l[maxn];
int r[maxn];
int main()
{
//test;
int n=read();
for(int i=1;i<=n;i++)
a[i]=read();
a[0]=-1,a[n+1]=-1;

for(int i=1;i<=n;i++)
{
int j=i-1;
while(a[j]>=a[i])j=l[j];
l[i]=j;
}
for(int i=n;i>=1;i--)
{
int j=i+1;
while(a[j]>=a[i])j=r[j];
r[i]=j;
}
for(int i=1;i<=n;i++)
{
int len=r[i]-l[i]-1;
dp[len]=max(dp[len],a[i]);
}
for(int i=n-1;i>=1;i--)
dp[i]=max(dp[i+1],dp[i]);
for(int i=1;i<=n;i++)
cout<<dp[i]<<" ";
}

10
1 2 3 4 5 4 3 2 1 6