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。
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/* *********************************************** 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; } |
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