P2340 [USACO03FALL] Cow Exhibition G

合集 - 动态规划dp(55)

1.P8784 [蓝桥杯 2022 省 B] 积木画2024-02-172.P9847 [ICPC2021 Nanjing R] Crystalfly2024-02-183.G. Vlad and Trouble at MIT2024-02-204.P2899 [USACO08JAN] Cell Phone Network G2024-02-205.P5322 [BJOI2019] 排兵布阵2024-03-036.P2946 [USACO09MAR] Cow Frisbee Team S2024-03-037.P1156 垃圾陷阱2024-03-038.P1064 [NOIP2006 提高组] 金明的预算方案2024-03-049.P2466 [SDOI2008] Sue 的小球2024-03-0410.P5020 [NOIP2018 提高组] 货币系统2024-03-0411.P1757 通天之分组背包2024-03-0412.P2135 方块消除2024-03-0613.D - String Bags2024-03-1014.P4395 [BOI2003] Gem 气垫车2024-03-1015.A - A Multiply2024-03-2416.P2642 双子序列最大和2024-03-2517.P1121 环状最大两段子段和2024-03-2518.P2422 良好的感觉2024-03-2519.P2854 [USACO06DEC] Cow Roller Coaster S2024-03-2620.C. Theofanis' Nightmare2024-03-2721.D. Birthday Gift2024-03-2722.P1284 三角形牧场2024-03-2823.P1353 [USACO08JAN] Running S2024-03-2824.P8736 [蓝桥杯 2020 国 B] 游园安排2024-03-3025.P1470 [USACO2.3] 最长前缀 Longest Prefix2024-04-0126.P7859 [COCI2015-2016#2] GEPPETTO2024-04-0527.P1435 [IOI2000] 回文字串2024-05-08

28.P2340 [USACO03FALL] Cow Exhibition G2024-05-13

29.P1854 花店橱窗布置2024-05-1330.P3147 [USACO16OPEN] 262144 P2024-05-1331.Game on Tree2024-05-1432.P2938 [USACO09FEB] Stock Market G2024-05-1833.P9691 [GDCPC2023] Base Station Construction2024-05-1834.P8624 [蓝桥杯 2015 省 AB] 垒骰子2024-05-2035.E. Money Buys Happiness2024-05-2236.P8675 [蓝桥杯 2018 国 B] 搭积木2024-05-2237.P8774 [蓝桥杯 2022 省 A] 爬树的甲壳虫2024-05-2238.P8806 [蓝桥杯 2022 国 B] 搬砖2024-05-2339.P5662 [CSP-J2019] 纪念品2024-05-2440.B. Mashmokh and ACM2024-06-0841.C. Minimizing the Sum2024-06-1242.H. Don't Blame Me2024-06-1343.D. Bicolorings2024-06-1444.D. Armchairs2024-06-1845.C. Chef Monocarp2024-06-1846.D. Invertible Bracket Sequences2024-06-2047.P1351 [NOIP2014 提高组] 联合权值2024-06-2648.D. World is Mine2024-07-0249.F. Feed Cats2024-07-0750.P3522 [POI2011] TEM-Temperature2024-07-2151.P3572 [POI2014] PTA-Little Bird2024-07-2252.P3089 [USACO13NOV] Pogo-Cow S2024-07-2253.E - Maximum Glutton2024-07-2854.Projects2024-07-2855.Elevator Rides2024-07-28

收起

原题链接

题解

1.考虑到每个牛只有选或不选两种选择，这样暴力搜索的思路便产生了
2.还是上面的思路，怎么优化呢？
想想背包数组，其下标是什么？是体积
其值是是什么？是价值
是在体积相同的情况下选择价值最高的，本题也是，最优解一定是相同智商里情商最高的
3.价值和体积都是负数，怎么解决？

code

#include<bits/stdc++.h>
using namespace std;
int dp[800008]={0},vis[800008]={0};
struct
{
    int i,e;
}cow[405];
int main()
{
    memset(dp,-0x3f,sizeof dp);
    dp[400000]=0;//移动坐标轴，把400000看成零点
    vis[400000]=1;
    int n;
    cin>>n;
    int tot=0;
    for(int i=1;i<=n;i++) cin>>cow[i].i>>cow[i].e;


    for(int i=1;i<=n;i++)
    {
        if(cow[i].i>=0)
        {
            for(int k=800000;k>=cow[i].i;k--)
            {
                if(vis[k-cow[i].i])
                {
                    dp[k]=max(dp[k],dp[k-cow[i].i]+cow[i].e);
                    //printf("%d:%d\n",k,dp[k]);
                    vis[k]=1;
                }
            }
        }
        else
        {
            for(int k=0;k<=800000+cow[i].i;k++)//如果智商是负数，滚动数组要倒着来
            {
                if(vis[k-cow[i].i])
                {
                    dp[k]=max(dp[k],dp[k-cow[i].i]+cow[i].e);
                    //printf("%d:%d\n",k,dp[k]);
                    vis[k]=1;
                }
            }
        }
    }

    int ans=0;
    for(int i=400000;i<=800000;i++)
    {
        if(vis[i]&&dp[i]>=0)ans=max(ans,dp[i]+i-400000);
    }
    cout<<ans;
    return 0;
}