codeforces 279 B books
http://codeforces.com/problemset/problem/279/B 题意：给定一个序列，问一段连续的序列的和小于等于t的最长的序列的长度。 思路：尺取法。三个月前学习的了。
/* ***********************************************
Author :111qqz
Created Time :2015年12月15日 星期二 20时08分16秒
File Name :code/cf/problem/279B.cpp
************************************************ */
1#include <cstdio>
2#include <cstring>
3#include <iostream>
4#include <algorithm>
5#include <vector>
6#include <queue>
7#include <set>
8#include <map>
9#include <string>
10#include <cmath>
11#include <cstdlib>
12#include <ctime>
13#define fst first
14#define sec second
15#define lson l,m,rt<<1
16#define rson m+1,r,rt<<1|1
17#define ms(a,x) memset(a,x,sizeof(a))
18typedef long long LL;
19#define pi pair < int ,int >
20#define MP make_pair
1using namespace std;
2const double eps = 1E-8;
3const int dx4[4]={1,0,0,-1};
4const int dy4[4]={0,-1,1,0};
5const int inf = 0x3f3f3f3f;
6const int N=1E5+7;
7int n;
8int t;
9int a[N];
1void solve()
2{
3 int head = 1;
4 int tail = 1;
5 int sum = 0 ;
6 int ans = 0 ;
7 while (tail<=n)
8 {
9// cout<<"aaaaa?"<<endl;
10 sum = sum + a[tail];
11// cout<<"head:"<<head<<" tail:"<<tail<<" sum:"<<sum<<endl;
12 if (sum>t)
13 {
14 while (sum>t)
15 {
16 sum = sum - a[head];
17// cout<<"sum:"<<sum<<endl;
18 head++;
19 }
20 }
21 if (sum<=t)
22 ans = max(ans,tail-head+1);
23 tail++;
1 }
2 printf("%d\n",ans);
3}
4int main()
5{
6 #ifndef ONLINE_JUDGE
7 freopen("code/in.txt","r",stdin);
8 #endif
1 scanf("%d%d",&n,&t);
2 for ( int i =1 ; i <= n ; i++) scanf("%d",&a[i]);
3 solve();
1 #ifndef ONLINE_JUDGE
2 fclose(stdin);
3 #endif
4 return 0;
5}