hdu5726 GCD(gcd +二分+rmq)

Problem Description
Give you a sequence of  N(N100,000) integers :  a1,...,an(0<ai1000,000,000). There are  Q(Q100,000) queries. For each query  l,r you have to calculate  gcd(al,,al+1,...,ar) and count the number of pairs (l,r)(1l<rN)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<ai1000,000,000).

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

题意:给你n个数,m个询问,每一个询问都是一个区间,让你先计算出这段区间所有数的gcd,然后问1~n所有连续区间中gcd的值等于询问区间gcd的区间个数。

思路:考虑到如果固定区间左端点L,那么右端点从L+1变化到n的过程中gcd最多变化log(区间内最大的数的大小)次(因为每次变化至少除以2),那么我们就可以枚举左端点,然后每次二分值连续的区间,然后都存到map里就行了。

#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
using namespace std;
#define lson th<<1
#define rson th<<1|1
typedef long long ll;
typedef long double ldb;
#define inf 99999999
#define pi acos(-1.0)
#define Key_value ch[ch[root][1]][0]
mapmp;
map::iterator it;

int q[100100][2];

int gcd(int a,int b){
    return b?gcd(b,a%b):a;
}
int gcd1[100100][30];

int a[100006];
void init_rmq(int n)
{
    int i,j;
    for(i=1;i<=n;i++){
        gcd1[i][0]=a[i];
    }

    for(j=1;j<=20;j++){
        for(i=1;i<=n;i++){
            if(i+(1<r)swap(l,r);
    k=(log((r-l+1)*1.0)/log(2.0));
    return gcd(gcd1[l][k],gcd1[r-(1<%d\n",i);
            int val=a[i];
            int pos=i;
            while(pos<=n){
                val=getgcd(i,pos);
                l=pos,r=n;
                while(l<=r){
                    mid=(l+r)/2;
                    if(getgcd(i,mid)==val)l=mid+1;
                    else r=mid-1;
                }
                mp[val]+=(r-pos+1);
                pos=l;
            }

        }
        scanf("%d",&m);
        for(i=1;i<=m;i++){
            scanf("%d%d",&q[i][0],&q[i][1]);
        }
        printf("Case #%d:\n",++cas);
        for(i=1;i<=m;i++){
            printf("%d %lld\n",getgcd(q[i][0],q[i][1]),mp[getgcd(q[i][0] ,q[i][1] ) ] );
        }
    }
    return 0;
}


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