首页 > 其他 > 详细

Subsequence poj 3061 二分(nlog n)或尺取法(n)

时间:2015-03-29 19:27:29      阅读:208      评论:0      收藏:0      [点我收藏+]
Subsequence
Time Limit: 1000MS   Memory Limit: 65536K
Total Submissions: 9236   Accepted: 3701

Description

A sequence of N positive integers (10 < N < 100 000), each of them less than or equal 10000, and a positive integer S (S < 100 000 000) are given. Write a program to find the minimal length of the subsequence of consecutive elements of the sequence, the sum of which is greater than or equal to S.

Input

The first line is the number of test cases. For each test case the program has to read the numbers N and S, separated by an interval, from the first line. The numbers of the sequence are given in the second line of the test case, separated by intervals. The input will finish with the end of file.

Output

For each the case the program has to print the result on separate line of the output file.if no answer, print 0.

Sample Input

2
10 15
5 1 3 5 10 7 4 9 2 8
5 11
1 2 3 4 5

Sample Output

2
3



二分代码:
 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <string>
 7 #include <vector>
 8 #include <set>
 9 #include <map>
10 #include <queue>
11 #include <stack>
12 #include <sstream>
13 #include <iomanip>
14 using namespace std;
15 const int INF=0x4fffffff;
16 const int EXP=1e-6;
17 const int MS=100005;
18 
19 int a[MS];
20 int sum[MS];
21 int N,S;
22 
23 int main()
24 {
25       int T;
26       scanf("%d",&T);
27       while(T--)
28       {
29             scanf("%d%d",&N,&S);
30             sum[0]=0;
31             a[0]=0;
32             for(int i=1;i<=N;i++)
33             {
34                   scanf("%d",&a[i]);
35                   sum[i]=a[i]+sum[i-1];
36             }
37             if(sum[N]<S)
38             {
39                   printf("0\n");
40                   continue;
41             }
42             int ans=N;
43             for(int i=1;sum[i-1]+S<=sum[N];i++)
44             {
45                   int index=lower_bound(sum+i,sum+N,sum[i-1]+S)-sum;
46                   ans=min(ans,index-i+1);
47             }
48             printf("%d\n",ans);
49       }
50       return 0;
51 }

 

 

尺取大法好啊

 

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <string>
 7 #include <vector>
 8 #include <set>
 9 #include <map>
10 #include <queue>
11 #include <stack>
12 #include <sstream>
13 #include <iomanip>
14 using namespace std;
15 const int INF=0x4fffffff;
16 const int EXP=1e-6;
17 const int MS=100005;
18 
19 int a[MS];
20 int N,S;
21 
22 int main()
23 {
24       int T;
25       scanf("%d",&T);
26       while(T--)
27       {
28             scanf("%d%d",&N,&S);
29             for(int i=0;i<N;i++)
30                   scanf("%d",&a[i]);
31             int sum=0;
32             int s=0,t=0;
33             int ans=N+1;
34             while(1)
35             {
36                   while(t<N&&sum<S)
37                         sum+=a[t++];
38                   if(sum<S)
39                         break;
40                   ans=min(ans,t-s);
41                   sum-=a[s++];
42             }
43             if(ans>N)
44                   printf("0\n");
45             else
46                   printf("%d\n",ans);
47       }
48       return 0;
49 }

 

Subsequence poj 3061 二分(nlog n)或尺取法(n)

原文:http://www.cnblogs.com/767355675hutaishi/p/4376062.html

(0)
(0)
   
举报
评论 一句话评论(0
关于我们 - 联系我们 - 留言反馈 - 联系我们:wmxa8@hotmail.com
© 2014 bubuko.com 版权所有
打开技术之扣,分享程序人生!