Codeforces Round #276 (Div. 1) E. Sign on Fence 二分+主席树
Bizon the Champion has recently finished painting his wood fence. The fence consists of a sequence of n panels of 1 meter width and of arbitrary height. The i-th panel's height is hi meters. The adjacent planks follow without a gap between them.
After Bizon painted the fence he decided to put a "for sale" sign on it. The sign will be drawn on a rectangular piece of paper and placed on the fence so that the sides of the sign are parallel to the fence panels and are also aligned with the edges of some panels. Bizon the Champion introduced the following constraints for the sign position:
- The width of the sign should be exactly w meters.
- The sign must fit into the segment of the fence from the l-th to the r-th panels, inclusive (also, it can't exceed the fence's bound in vertical direction).
The sign will be really pretty, So Bizon the Champion wants the sign's height to be as large as possible.
You are given the description of the fence and several queries for placing sign. For each query print the maximum possible height of the sign that can be placed on the corresponding segment of the fence with the given fixed width of the sign.
The first line of the input contains integer n — the number of panels in the fence (1 ≤ n ≤ 105).
The second line contains n space-separated integers hi, — the heights of the panels (1 ≤ hi ≤ 109).
The third line contains an integer m — the number of the queries (1 ≤ m ≤ 105).
The next m lines contain the descriptions of the queries, each query is represented by three integers l, r and w (1 ≤ l ≤ r ≤ n, 1 ≤ w ≤ r - l + 1) — the segment of the fence and the width of the sign respectively.
For each query print the answer on a separate line — the maximum height of the sign that can be put in the corresponding segment of the fence with all the conditions being satisfied.
5
1 2 2 3 3
3
2 5 3
2 5 2
1 5 5
2
3
1
The fence described in the sample looks as follows:

The possible positions for the signs for all queries are given below.
The optimal position of the sign for the first query.
The optimal position of the sign for the second query.
The optimal position of the sign for the third query.
题意:
给你n个数,每个数表示一个高度。
m个询问,每次询问你l,r内连续w个数的最低高度的最大值
note解释样例很详细
题解:
主席树的技巧
按照高度排序,倒着插入每一颗线段树中
查询的话,二分历史版本线段树的位置,在l,r这段区间内至少存在连续w个位置存在有值,很明显的线段树的区间合并,区间查询了
#include<bits/stdc++.h>
using namespace std;
#pragma comment(linker, "/STACK:102400000,102400000")
#define ls i<<1
#define rs ls | 1
#define mid ((ll+rr)>>1)
#define pii pair<int,int>
#define MP make_pair
typedef long long LL;
const long long INF = 1e18;
const double Pi = acos(-1.0);
const int N = 1e5+, M = 1e6, mod = 1e9+, inf = 2e9;
int n,root[N],m,l[N*],r[N*],rmx[N*],lmx[N*],mx[N*],sz,v[N*];
pair<int ,int > a[N];
void push_up(int i,int ll,int rr) {
lmx[i] = lmx[l[i]];
if(lmx[i] == mid - ll + ) lmx[i] += lmx[r[i]];
rmx[i] = rmx[r[i]];
if(rmx[i] == rr - mid) rmx[i] += rmx[l[i]];
mx[i] = max(lmx[r[i]]+rmx[l[i]],max(mx[l[i]],mx[r[i]]));
}
void update(int x,int &y,int ll,int rr,int k,int c) {
v[y = ++sz] = v[x] + ;
l[y] = l[x];
r[y] = r[x];
if(ll == rr) {
mx[y] = lmx[y] = rmx[y] = c;
l[y] = ; r[y] = ;
return ;
}
if(k <= mid) update(l[x],l[y],ll,mid,k,c);
else update(r[x],r[y],mid+,rr,k,c);
push_up(y,ll,rr);
}
int query(int i,int ll,int rr,int s,int t) {
if(s > t) return ;
if(s == ll && rr == t) return mx[i];
int ret = ;
if(t <= mid) ret = query(l[i],ll,mid,s,t);
else if(s > mid) ret = query(r[i],mid+,rr,s,t);
else {
ret = max(query(l[i],ll,mid,s,mid),query(r[i],mid+,rr,mid+,t));
int lx = min(rmx[l[i]],mid - s + );
int rx = min(lmx[r[i]],t - mid);
ret = max(ret, lx + rx);
}
return ret;
}
int main() {
scanf("%d",&n);
for(int i = ; i <= n; ++i) scanf("%d",&a[i].first),a[i].second = i;
sort(a+,a+n+);
for(int i = n; i >= ; --i) update(root[i+],root[i],,n,a[i].second,);
scanf("%d",&m);
for(int i = ; i <= m; ++i) {
int x,y,w;
scanf("%d%d%d",&x,&y,&w);
int l = , r = n, ans = n;
while(l <= r) {
int md = (l+r)>>;
int ss = query(root[md],,n,x,y);
if(ss >= w) l = md+,ans=md;
else r = md - ;
}
printf("%d\n",a[ans].first);
}
return ;
}
Codeforces Round #276 (Div. 1) E. Sign on Fence 二分+主席树的更多相关文章
- CF&&CC百套计划4 Codeforces Round #276 (Div. 1) E. Sign on Fence
http://codeforces.com/contest/484/problem/E 题意: 给出n个数,查询最大的在区间[l,r]内,长为w的子区间的最小值 第i棵线段树表示>=i的数 维护 ...
- Codeforces Round #276 (Div. 1) E. Sign on Fence (二分答案 主席树 区间合并)
链接:http://codeforces.com/contest/484/problem/E 题意: 给你n个数的,每个数代表高度: 再给出m个询问,每次询问[l,r]区间内连续w个数的最大的最小值: ...
- Codeforces Round #365 (Div. 2) C - Chris and Road 二分找切点
// Codeforces Round #365 (Div. 2) // C - Chris and Road 二分找切点 // 题意:给你一个凸边行,凸边行有个初始的速度往左走,人有最大速度,可以停 ...
- 【CF484E】Sign on Fence(主席树)
[CF484E]Sign on Fence(主席树) 题面 懒得贴CF了,你们自己都找得到 洛谷 题解 这不就是[TJOI&HEOI 排序]那题的套路吗... 二分一个答案,把大于答案的都变成 ...
- Codeforces Round #276 (Div. 1) D. Kindergarten dp
D. Kindergarten Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/problemset/proble ...
- Codeforces Round #276 (Div. 1) B. Maximum Value 筛倍数
B. Maximum Value Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/484/prob ...
- Codeforces Round #276 (Div. 1) A. Bits 二进制 贪心
A. Bits Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/484/problem/A Des ...
- Codeforces Round #276 (Div. 2) 解题报告
题目地址:http://codeforces.com/contest/485 A题.Factory 模拟.判断是否出现循环,如果出现,肯定不可能. 代码: #include<cstdio> ...
- CF&&CC百套计划4 Codeforces Round #276 (Div. 1) A. Bits
http://codeforces.com/contest/484/problem/A 题意: 询问[a,b]中二进制位1最多且最小的数 贪心,假设开始每一位都是1 从高位i开始枚举, 如果当前数&g ...
随机推荐
- poj 1182
http://poj.org/problem?id=1182 一个利用并查集的经典题目. 思路:在网上看到别人的思路,觉得方法还是挺不错的. 首先,开辟一个3*n的数组belg,用来存b和c的关系,在 ...
- POJ 1979
这是一道比较水的DPS的题目 题意就是求你可以走到的黑色的地板砖的块数,@代表你的起点,也是黑色的地板砖,#代表白色的,则说明你不能走,这就是一个广搜的题目 思路也很简单,如果你周围的那块地板是黑色的 ...
- 【转】CentOS5.6下配置rsync内网同步数据到外网
[转]CentOS5.6下配置rsync内网同步数据到外网 本文转自:http://www.linuxidc.com/Linux/2012-06/64070.htm 一.需求 卫士那边有一个需求,就是 ...
- Unity3d 制作物品平滑运动
直接贴代码了 using UnityEngine; using System; using System.Collections; using System; using DataTable; pub ...
- php bom \ufeff
2015年5月29日 16:50:56 星期五 五月的最后一个周五............. 前两天遇到一个问题 PHP 返回json数据, 其他人死活解析不出来 json_last_error(); ...
- uva 489.Hangman Judge 解题报告
题目链接:https://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&page=show_problem ...
- CSS3实现元素旋转
-webkit-transform:rotate(30deg); 参数代表顺时针自旋转角度 这个元素还提供了文本倾斜的方法 - HTML5与CSS3 P299
- 【leetcode】Maximal Rectangle (hard)★
Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing all ones and ...
- 【leetcode】Balanced Binary Tree(middle)
Given a binary tree, determine if it is height-balanced. For this problem, a height-balanced binary ...
- JSP题库
一. 填空题 一个完整的JSP页面是由普通的HTML标记.JSP指令标记.JSP动作标记. 变量声明 与方法声明 .程序片 .表达式 . 注释 7种要素构成. JSP页面的基本构 ...