原题链接 题目大意:这是一道好题.在<算法导论>这本书里面,有一节是介绍如何求最大子序列的.这道题有点类似,区别是从数组变成了矩阵,求最大子矩阵. 解法:完全没有算法功底的人当然不知道最大子序列这么经典的东西.所以先请教Google.我是参考了这篇文章的,tengpi.blog.163.com/blog/static/22788264200772561412895/.大意就是另开辟一个同样大小的矩阵,每个元素存放自左侧第一列到该元素的和.然后在纵向上用最大子序列的类似方法计算. 参考代码: /…

To the Max Time Limit: 2 Seconds      Memory Limit: 65536 KB Problem Given a two-dimensional array of positive and negative integers, a sub-rectangle is any contiguous sub-array of size 1 x 1 or greater located within the whole array. The sum of a re…

HDU 1074 Doing Homework (动态规划,位运算) Description Ignatius has just come back school from the 30th ACM/ICPC. Now he has a lot of homework to do. Every teacher gives him a deadline of handing in the homework. If Ignatius hands in the homework after the d…

Problem Description Given a two-dimensional array of positive and negative integers, a sub-rectangle is any contiguous sub-array of size 1 x 1 or greater located within the whole array. The sum of a rectangle is the sum of all the elements in that re…

题目链接: http://acm.hdu.edu.cn/showproblem.php?pid=1081 http://acm.xmu.edu.cn/JudgeOnline/problem.php?id=1031 题目大意: 给一个n*n(n<=100)的矩阵,求一个矩形覆盖的值最大是多少. 题目思路: [动态规划] 二维的最大字段和.先考虑一维的情况.f[i]=max(f[i-1]+a[i],a[i]) 只要之前的部分和大于零则一起取一定比只取当前位置的要优. 因此只要判断局部段的和是否大于零…

题目链接 Problem Description Given a two-dimensional array of positive and negative integers, a sub-rectangle is any contiguous sub-array of size 1 x 1 or greater located within the whole array. The sum of a rectangle is the sum of all the elements in th…

题目地址:http://poj.org/problem?id=1050 Description Given a two-dimensional array of positive and negative integers, a sub-rectangle is any contiguous sub-array of size 1*1 or greater located within the whole array. The sum of a rectangle is the sum of a…

Description Given a two-dimensional array of positive and negative integers, a sub-rectangle is any contiguous sub-array of size 1*1 or greater located within the whole array. The sum of a rectangle is the sum of all the elements in that rectangle. I…

题意:在给定的数组里,寻找一个最长的序列,满足ai-2+ai-1=ai.并输出这个序列. 很容易想到一个DP方程 dp[i][j]=max(dp[k][i])+1. (a[k]+a[i]==a[j],1<=k&&k<i) dp[i][j]表示序列最后两位是a[i],a[j]时的最长长度. 这个方程状态是O(n^2),转移是O(n),总复杂度是O(n^3)会超时. 进一步思考会发现转移这里是可以优化的.实际上我们只需要知道离i最近的那个满足a[k]+a[i]==a[j]的k就行,…

Description Given a two-dimensional array of positive and negative integers, a sub-rectangle is any contiguous sub-array of size 1*1 or greater located within the whole array. The sum of a rectangle is the sum of all the elements in that rectangle. I…

Description Given a two-dimensional array of positive and negative integers, a sub-rectangle is any contiguous sub-array of size 1*1 or greater located within the whole array. The sum of a rectangle is the sum of all the elements in that rectangle. I…

一.动态规划算法 众所周知,递归算法时间复杂度很高为(2^n),而动态规划算法也能够解决此类问题,动态规划的算法的时间复杂度为(n^2).动态规划算法是以空间置换时间的解决方式,一开始理解起来可能比较困难,自己画画也许明白了很多. 二.动态规划算法分析 先举个例子: {7,0,0,0,0},{3,8,0,0,0},{8,1,0,0,0},{2,7,4,4,0},{4,5,2,6,5} 这个二维数组,求一下,顶层到底层,只能通过两端来相加的最大值(也就是说这棵树的最长路径). 分析: (1)第一步…

acm之pku题目分类 对ACM有兴趣的同学们可以看看 DP:  1011   NTA                 简单题  1013   Great Equipment     简单题  1024   Calendar Game       简单题  1027   Human Gene Functions   简单题  1037   Gridland            简单题  1052   Algernon s Noxious Emissions 简单题  1409   Commun…

以下是poj百道水题,新手可以考虑从这里刷起 搜索1002 Fire Net1004 Anagrams by Stack1005 Jugs1008 Gnome Tetravex1091 Knight Moves1101 Gamblers1204 Additive equations 1221 Risk1230 Legendary Pokemon1249 Pushing Boxes 1364 Machine Schedule1368 BOAT1406 Jungle Roads1411 Annive…

package findMax; /** * 连续子数组的最大和 * @author root * */ public class FindMax { static int[] data = {1,-2,3,10,-4,7,2,-5}; public static void main(String[] args) { // TODO Auto-generated method stub find(); } //分析数据规律 public static void find(){ int max =…

题目地址:http://acm.hdu.edu.cn/showproblem.php?pid=1024 Problem Description Now I think you have got an AC in Ignatius.L's "Max Sum" problem. To be a brave ACMer, we always challenge ourselves to more difficult problems. Now you are faced with a mor…

Description Given a two-dimensional array of positive and negative integers, a sub-rectangle is any contiguous sub-array of size 1*1 or greater located within the whole array. The sum of a rectangle is the sum of all the elements in that rectangle. I…

HDOJ(HDU).1003 Max Sum (DP) 点我挑战题目 算法学习-–动态规划初探 题意分析 给出一段数字序列,求出最大连续子段和.典型的动态规划问题. 用数组a表示存储的数字序列,sum表示当前子段和,maxsum表示最大子段和.不妨设想:当sum为负数的时候: 1.当下一个数字a[i]为正数的时候,sum+a[i] < a[i],不如将sum归零重新计算 2.当下一个数字为负数的时候,sum+a[i]< 0 ,若再下一个数字还为负数,依旧可以得出和小于零--直到遇到一个正数,此…

一个注意点,就是sqlalchemy 使用create_all()建表的时候,要在 create_all()所在页面import那些表的model sqlalchemy.exc.OperationalError: (_mysql_exceptions.OperationalError) (1074, "Column length too big for column 'err_solution' (max = 21845); use BLOB or TEXT instead") [SQ…

题目传送门 /* 题意:在一个矩阵里放炮台,满足行列最多只有一个炮台,除非有墙(X)相隔,问最多能放多少个炮台 搜索(DFS):数据小,4 * 4可以用DFS,从(0,0)开始出发,往(n-1,n-1)左下角走,x = cnt / n; y = cnt % n; 更新坐标, 直到所有点走完为止,因为从左边走到右边,只要判断当前点左上方是否满足条件就可以了 注意:当前点不能放炮台的情况也要考虑 g[x][y] == 'o'; 的错误半天才检查出来:) */ #include <cstdio> #…

题目地址:http://acm.hdu.edu.cn/showproblem.php?pid=1423 Problem Description This is a problem from ZOJ 2432.To make it easyer,you just need output the length of the subsequence.   Input Each sequence is described with M - its length (1 <= M <= 500) and…

http://acm.hdu.edu.cn/showproblem.php?pid=1003 给出一个包含n个数字的序列{a1,a2,..,ai,..,an},-1000<=ai<=1000 求最大连续子段和及其起始位置和终止位置,很基础的动态规划(DP)问题,看完DP第一次做的DP题目 DP真的是一种很优美的算法,或者说思想,但是比较难理解,我对DP的理解还很浅薄 # include <stdio.h> # define INF 1000000000 int main() { i…

因为是circle sequence,可以在序列最后+序列前n项(或前k项);利用前缀和思想,预处理出前i个数的和为sum[i],则i~j的和就为sum[j]-sum[i-1],对于每个j,取最小的sum[i-1],这就转成一道单调队列了,维护k个数的最小值. ---------------------------------------------------------------------------------- #include<cstdio> #include<deque&…

Max Sum Plus Plus Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 29942    Accepted Submission(s): 10516 Problem Description Now I think you have got an AC in Ignatius.L's "Max Sum" problem…

Max Sum Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 250714    Accepted Submission(s): 59365 Problem Description Given a sequence a[1],a[2],a[3]......a[n], your job is to calculate the max su…

HDU 1024 Max Sum Plus Plus (动态规划) Description Now I think you have got an AC in Ignatius.L's "Max Sum" problem. To be a brave ACMer, we always challenge ourselves to more difficult problems. Now you are faced with a more difficult problem. Given…

Max Sum Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 193355 Accepted Submission(s): 45045 Problem Description Given a sequence a[1],a[2],a[3]--a[n], your job is to calculate the max sum of a su…

ZOJ 1081 Within 我使用的是"射线法":从该点出发,作一条向左的水平射线,与多边形的边的交点有奇数个则点在多边形内. 需要注意的点: 如果点在多边形的边上特判. 考虑射线与多边形的一个交点是多边形的顶点的情况, 最左边的那个顶点算一个交点,左边第二种的那个顶点算两个交点或不算交点都行(但不能算一个交点). #include <cstdio> #include <cstring> #include <cmath> #include <…

链接: http://acm.hdu.edu.cn/showproblem.php?pid=1081 这道题使用到的算法是:预处理+最大连续子串和 如果会做最大连续子串和,那么理解这题就相对简单一些,若不知道最大连续子串和,建议先看一下这两题: http://acm.hdu.edu.cn/showproblem.php?pid=1003 http://www.cnblogs.com/YY56/p/4855766.html To The Max Time Limit: 2000/1000 MS (…

To the Max Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others) Problem Description Given a two-dimensional array of positive and negative integers, a sub-rectangle is any contiguous sub-array of size 1*1 or greater locate…