Codeforces Round #436 (Div. 2) E. Fire(dp 记录路径)
2 seconds
256 megabytes
standard input
standard output
Polycarp is in really serious trouble — his house is on fire! It's time to save the most valuable items. Polycarp estimated that it would take tiseconds to save i-th item. In addition, for each item, he estimated the value of di — the moment after which the item i will be completely burned and will no longer be valuable for him at all. In particular, if ti ≥ di, then i-th item cannot be saved.
Given the values pi for each of the items, find a set of items that Polycarp can save such that the total value of this items is maximum possible. Polycarp saves the items one after another. For example, if he takes item a first, and then item b, then the item a will be saved in ta seconds, and the item b — in ta + tb seconds after fire started.
The first line contains a single integer n (1 ≤ n ≤ 100) — the number of items in Polycarp's house.
Each of the following n lines contains three integers ti, di, pi (1 ≤ ti ≤ 20, 1 ≤ di ≤ 2 000, 1 ≤ pi ≤ 20) — the time needed to save the item i, the time after which the item i will burn completely and the value of item i.
In the first line print the maximum possible total value of the set of saved items. In the second line print one integer m — the number of items in the desired set. In the third line print m distinct integers — numbers of the saved items in the order Polycarp saves them. Items are 1-indexed in the same order in which they appear in the input. If there are several answers, print any of them.
3
3 7 4
2 6 5
3 7 6
11
2
2 3
2
5 6 1
3 3 5
1
1
1
In the first example Polycarp will have time to save any two items, but in order to maximize the total value of the saved items, he must save the second and the third item. For example, he can firstly save the third item in 3 seconds, and then save the second item in another 2seconds. Thus, the total value of the saved items will be 6 + 5 = 11.
In the second example Polycarp can save only the first item, since even if he immediately starts saving the second item, he can save it in 3seconds, but this item will already be completely burned by this time.
【题意】有n件物品,起火了,救每件物品需要花t[i]时间,且必须在d[i]时刻之前完成,救下之后价值为p[i],求最大价值。
【分析】背包吧,dp很好写,dp[i][j]表示在j时刻救下i所得最大价值,关键是记录路径,更新时,将pos[i][j]更新为1,否则更新为0.
#include <bits/stdc++.h>
#define inf 0x3f3f3f3f
#define met(a,b) memset(a,b,sizeof a)
#define pb push_back
#define mp make_pair
#define rep(i,l,r) for(int i=(l);i<=(r);++i)
#define inf 0x3f3f3f3f
using namespace std;
typedef long long ll;
const int N = 1e2+;;
const int M = ;
const int mod = ;
const int mo=;
const double pi= acos(-1.0);
typedef pair<int,int>pii;
int n,s,ans,now=;
int dp[];
int pos[][];
struct man{
int t,d,p,id;
}a[];
bool cmp(const man&s,const man&t){
if(s.d==t.d)return s.t<t.t;
return s.d<t.d;
}
int main(){
scanf("%d",&n);
for(int i=;i<=n;i++){
scanf("%d%d%d",&a[i].t,&a[i].d,&a[i].p);
a[i].id=i;
}
sort(a+,a++n,cmp);
for(int i=;i<=n;i++){
if(a[i].t>a[i].d)continue;
for(int j=a[i].d-;j>=a[i].t;j--){
if(dp[j]<dp[j-a[i].t]+a[i].p){
dp[j]=dp[j-a[i].t]+a[i].p;
pos[a[i].id][j]=a[i].id;
}
else{
pos[a[i].id][j]=;
}
}
}
int maxn=,now=;
for(int i=;i<=;i++){
if(dp[i]>maxn){
maxn=dp[i];
now=i;
}
}
stack<int>s;
printf("%d\n",maxn);
for(int i=n;i>=;i--){
int id=a[i].id;
if(pos[id][now]){
s.push(id);
now-=a[i].t;
}
}
printf("%d\n",s.size());
while(!s.empty()){
printf("%d ",s.top());
s.pop();
}
return ;
}
Codeforces Round #436 (Div. 2) E. Fire(dp 记录路径)的更多相关文章
- Codeforces Round #436 (Div. 2) E. Fire
http://codeforces.com/contest/864/problem/E 题意: 有一堆物品,每个物品有3个属性,需要的时间,失效的时间(一开始)和价值.只能一件一件的选择物品(即在选择 ...
- Codeforces Round #436 (Div. 2) E. Fire(背包+记录路径)
传送门 题意 给出n种物品,抢救第\(i\)种物品花费时间\(t_i\),价值\(p_i\),截止时间\(d_i\) 询问抢救的顺序及物品价值和最大值 分析 按\(d_i\)排序的目的是防止以下情况 ...
- Codeforces Round #436 (Div. 2)【A、B、C、D、E】
Codeforces Round #436 (Div. 2) 敲出一身冷汗...感觉自己宛如智障:( codeforces 864 A. Fair Game[水] 题意:已知n为偶数,有n张卡片,每张 ...
- Codeforces Round #131 (Div. 1) B. Numbers dp
题目链接: http://codeforces.com/problemset/problem/213/B B. Numbers time limit per test 2 secondsmemory ...
- Codeforces Round #131 (Div. 2) B. Hometask dp
题目链接: http://codeforces.com/problemset/problem/214/B Hometask time limit per test:2 secondsmemory li ...
- 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 #260 (Div. 1) A - Boredom DP
A. Boredom Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/455/problem/A ...
- Codeforces Round #436 (Div. 2)
http://codeforces.com/contest/864 第一次打cf的月赛-- A 题意:给你一个数列,问你能不能保证里面只有两种数且个数相等.2<=n<=100,1<= ...
- Codeforces Round #533 (Div. 2) C.思维dp D. 多源BFS
题目链接:https://codeforces.com/contest/1105 C. Ayoub and Lost Array 题目大意:一个长度为n的数组,数组的元素都在[L,R]之间,并且数组全 ...
随机推荐
- NOIP 2000 方格取数
https://www.luogu.org/problem/show?pid=1004 题目描述 设有N*N的方格图(N<=9),我们将其中的某些方格中填入正整数,而其他的方格中则放 人数字0. ...
- 字符串:KMP
KMP是字符串匹配的经典算法 也是众多字符串基础的重中之重 A. 题意:给T组数据,每组有长度为n和m的母串和模式串.判断模式串是否是母串的子串,如果是输出最先匹配完成的位置,否则输出-1. 做法:直 ...
- (4.1)LingPipe在Eclipse中的运行
酒店评论情感分析系统(四)——LingPipe在Eclipse中的运行 本来打算在做这个项目的时候,使用基于语义的文本倾向性分析方法,即先通过对评论文本进行中文分析,去停用词,然后在倾向性语义模式库的 ...
- 【CodeForces】913 F. Strongly Connected Tournament 概率和期望DP
[题目]F. Strongly Connected Tournament [题意]给定n个点(游戏者),每轮游戏进行下列操作: 1.每对游戏者i和j(i<j)进行一场游戏,有p的概率i赢j(反之 ...
- Callback2.0
Callback定义? a callback is a piece of executable code that is passed as an argument to other code, wh ...
- java反序列化漏洞
http://www.freebuf.com/vuls/86566.html 有时间了 仔细阅读
- 关于ORA-04091异常的出现原因,以及解决方案
问题分析 在Oracle中执行DML语句的时候是需要显示进行提交操作的.当我们进行插入的时候,会触发触发器执行对触发器作用表和扩展表的种种操作,但是这个时 候触发器和插入语句是在同一个事务管理中的,因 ...
- 统计学习方法三:K近邻
一.什么是K近邻? K近邻是一种基本的分类和回归方法. 在分类时,对新的实例,根据其K个最近邻的训练实例的类别,通过多数表决权等方式预测其类别. 通俗的讲,找K个和其关系最近的邻居,哪个类别的邻居多, ...
- /bin、/sbin、/usr/bin、/usr/sbin目录Linux执行文档的区别
/bin./sbin./usr/bin./usr/sbin目录的区别 在linux下我们经常用到的四个应用程序的目录是/bin./sbin./usr/bin./usr/sbin .而四者存放的文件 ...
- npm install 装本地一直安装全局问题
想用npm安装一些模块,不管怎么装,一直装作全局. 以为是node有问题,重装了N次,却还发现这个问题. 困惑几天无果, 偶然间通过此文章发现,npm存在配置文件:https://www.sitepo ...