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
************************************************ */

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <cmath>
#include <cstdlib>
#include <ctime>
#define fst first
#define sec second
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define ms(a,x) memset(a,x,sizeof(a))
typedef long long LL;
#define pi pair < int ,int >
#define MP make_pair

using namespace std;
const double eps = 1E-8;
const int dx4[4]={1,0,0,-1};
const int dy4[4]={0,-1,1,0};
const int inf = 0x3f3f3f3f;
const int N=1E5+7;
int n;
int t;
int a[N];

void solve()
{
    int head = 1;
    int tail = 1;
    int sum = 0 ;
    int ans = 0 ;
    while (tail<=n)
    {
//	cout<<"aaaaa?"<<endl;
	sum = sum + a[tail];
//	cout<<"head:"<<head<<" tail:"<<tail<<" sum:"<<sum<<endl;
	if (sum>t)
	{
	    while (sum>t)
	    {
		sum = sum - a[head];
//		cout<<"sum:"<<sum<<endl;
		head++;
	    }
	}
	if (sum<=t)
	    ans = max(ans,tail-head+1);
	tail++;

    }
    printf("%d\n",ans);
}
int main()
{
	#ifndef  ONLINE_JUDGE 
	freopen("code/in.txt","r",stdin);
  #endif

	scanf("%d%d",&n,&t);
	for ( int i =1 ; i  <= n ; i++) scanf("%d",&a[i]);
	solve();

  #ifndef ONLINE_JUDGE  
  fclose(stdin);
  #endif
    return 0;
}