贪心的选择单调的序列进行划分
dp处理拐点(gd)应该分到左边的单调序列还是右边的单调序列
大量读入加输入挂
D. Kindergarten
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output
In a kindergarten, the children are being divided into groups. The teacher put the children in a line and associated each child with his or her integer charisma value. Each child should go to exactly one group. Each group should be a nonempty segment of consecutive children of a line. A group’ssociabilityis the maximum difference of charisma of two children in the group (in particular, if the group consists of one child, its sociability equals a zero).
The teacher wants to divide the children into some number of groups in such way that the totalsociabilityof the groups is maximum. Help him find this value.
Input
The first line contains integern— the number of children in the line (1≤n≤106).
The second line containsnintegersai— the charisma of thei-th child (-109≤ai≤109).
Output
Print the maximum possible total sociability of all groups.
Sample test(s)
input
51 2 3 1 2
output
3
input
33 3 3
output
0
Note
In the first test sample one of the possible variants of an division is following: the first three children form a group with sociability 2, and the two remaining children form a group with sociability 1.
In the second test sample any division leads to the same result, the sociability will be equal to 0 in each group.
/* ***********************************************Author:CKbossCreated Time :2015年03月10日 星期二 21时54分06秒File Name:CF484D_2.cpp************************************************ */#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>#include <string>#include <cmath>#include <cstdlib>#include <vector>#include <queue>#include <set>#include <map>using namespace std;typedef long long int LL;const int maxn=1009000;int n;LL a[maxn],dp[maxn];LL getLL(){char ch; bool flag=true;LL ret=0; LL fg=1;while(ch=getchar()){if((ch>='0'&&ch<='9')||ch=='-') {if(flag) flag=false;if(ch=='-') fg=-1;else ret=ret*10LL+ch-'0';}else if(flag==false) break;}return ret*fg;}int main(){//freopen("in.txt","r",stdin);//freopen("out.txt","w",stdout);scanf("%d",&n);getchar();for(int i=1;i<=n;i++) a[i]=getLL();int gd=1;bool up;if(a[2]>a[1]) up=true;else up=false;for(int i=2;i<=n;i++){if(a[i-1]<a[i]) /// up{if(up==true){dp[i]=max(a[i]-a[gd]+dp[gd-1],a[i]-a[gd+1]+dp[gd]);}else if(up==false) /// change gd{up=true; gd=i-1;dp[i]=max(dp[gd],dp[gd-1]+a[i]-a[gd]);}}else if(a[i-1]>a[i]) /// down{if(up==true) /// change gd{up=false; gd=i-1;dp[i]=max(dp[gd],dp[gd-1]+a[gd]-a[i]);}else if(up==false){dp[i]=max(a[gd]-a[i]+dp[gd-1],a[gd+1]-a[i]+dp[gd]);}}else if(a[i-1]==a[i]){/// new gdgd=i; up=true;dp[i]=dp[i-1];}}cout<<dp[n]<<endl;return 0;}
，积极的人在每一次忧患中都看到一个机会，
