GCD
Time Limit: 10000/5000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 1497 Accepted Submission(s): 483
Problem Description
Give you a sequence of N(N≤100,000) integers : a1,...,an(0<ai≤1000,000,000). There are Q(Q≤100,000) queries. For each query l,r you have to calculate gcd(al,,al+1,...,ar) and count the number of pairs(l′,r′)(1≤l<r≤N)such that gcd(al′,al′+1,...,ar′) equal gcd(al,al+1,...,ar).
Input
The first line of input contains a number T, which stands for the number of test cases you need to solve.The first line of each case contains a number N, denoting the number of integers.The second line contains N integers, a1,...,an(0<ai≤1000,000,000).The third line contains a number Q, denoting the number of queries.For the next Q lines, i-th line contains two number , stand for the li,ri, stand for the i-th queries.
Output
For each case, you need to output “Case #:t” at the beginning.(with quotes, t means the number of the test case, begin from 1).For each query, you need to output the two numbers in a line. The first number stands for gcd(al,al+1,...,ar) and the second number stands for the number of pairs(l′,r′) such that gcd(al′,al′+1,...,ar′) equal gcd(al,al+1,...,ar).
Sample Input
1 5 1 2 4 6 7 4 1 5 2 4 3 4 4 4
Sample Output
Case #1: 1 8 2 4 2 4 6 1
Author
HIT
Source
1
思路:RMQ+二分
一开始我用的线段树去维护各个区间的gcd但是超时,并且我没有优化。
暴力统计的各个区间的gcd;
后来发现gcd的性质,也就是求数的gcd,这些数的个数越多那么gcd越小,所以从左到右,以某个端点开始的gcd的大小随着区间增大而减小,那么二分统计以某个点为端点的gcd
最多每个端点二分30次。
然后还是超时。
然后改用RMQ基于稀疏表的,查询O(n);
复杂度(n*log(n));
1 #include2 #include 3 #include 4 #include 5 #include 6 #include 7 #include