传送门:http://acm.hdu.edu.cn/showproblem.php?pid=1024
Max Sum Plus Plus
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 35988 Accepted Submission(s): 12807
Given a consecutive number sequence S1, S2, S3, S4 ... Sx, ... Sn (1 ≤ x ≤ n ≤ 1,000,000, -32768 ≤ Sx ≤ 32767). We define a function sum(i, j) = Si + ... + Sj (1 ≤ i ≤ j ≤ n).
Now given an integer m (m > 0), your task is to find m pairs of i and j which make sum(i1, j1) + sum(i2, j2) + sum(i3, j3) + ... + sum(im, jm) maximal (ix ≤ iy ≤ jx or ix ≤ jy ≤ jx is not allowed).
But I`m lazy, I don't want to write a special-judge module, so you don't have to output m pairs of i and j, just output the maximal summation of sum(ix, jx)(1 ≤ x ≤ m) instead. ^_^
Process to the end of file.
2 6 -1 4 -2 3 -2 3
8
Huge input, scanf and dynamic programming is recommended.
#include<stdio.h>
#include<iostream>
#include<math.h>
#include<string.h>
#include<set>
#include<map>
#include<list>
#include<algorithm>
using namespace std;
typedef long long LL;
int mon1[]= {,,,,,,,,,,,,};
int mon2[]= {,,,,,,,,,,,,};
int dir[][]={{,},{,-},{,},{-,}}; #define INF 0x7fffffff//无穷大
#define max_v 1000010
int a[max_v];
int now[max_v];// now[j]:包含第j个元素的最大和
int pre[max_v];// pre[j]:前j个元素的最大和,不包括第j个元素
int main()
{
int n,m,maxx;
while(~scanf("%d %d",&m,&n))
{
for(int i=;i<=n;i++)
scanf("%d",&a[i]);
memset(now,,sizeof(now));
memset(pre,,sizeof(pre));
for(int i=;i<=m;i++)//m个子段
{
maxx=-INF;
for(int j=i;j<=n;j++)
{
now[j]=max(now[j-]+a[j],pre[j-]+a[j]);
//now[j] 有两种来源,一种是直接在第i个子段后面加a[j],一种是a[j]单独成为一个子段
pre[j-]=maxx;//更新pre使得pre[j-1]是前j-1个中的最大子段和
maxx=max(now[j],maxx);
}
}
printf("%d\n",maxx);
}
return ;
}