HDU5869树状数组+gcd预处理

比赛的时候知道用树状数组，但有点乱不知道怎么处理。

统计不同的gcd的个数其实就是用树状数组统计区间内不同的数的模板题啊...

复杂度O(nlogn)

#include <bits/stdc++.h>
using namespace std;
const int N = 1e5+10;
int n,q,i,j,a[N],l[N],v[N];
int fun(int x,int y){return __gcd(x,y);}

struct p{
    int l, r, ans, k;
};
p query[N];
bool cmp1(const p& a, const p& b){
    return a.r < b.r;
}
bool cmp2(const p& a, const p& b){
    return a.k < b.k;
}

int c[N], last[N*10], maxn;
int lowbit(int x){ return x&-x;}
void add(int x, int d){
    for(int i = x; i <= n; i += lowbit(i))
        c[i] += d;
}
int sum(int x){
    int ret = 0;
    while(x){
        ret += c[x];
        x -= lowbit(x);
    }
    return ret;
}

int main(){
    while(~scanf("%d%d", &n, &q)){
        maxn = -1;
        for(i = 1; i <= n; i++) scanf("%d", a+i), maxn = max(maxn, a[i]);
        for(i = 1; i <= q; i++){
            scanf("%d%d", &query[i].l, &query[i].r);
            query[i].k = i;
        }
        sort(query+1, query+q+1, cmp1);
        memset(last, 0, sizeof(int)*(maxn+5));
        memset(c, 0, sizeof(int)*(n+5));

        int qq  = 1;
        for(i = 1; i <= n; i++){
            for(v[i] = a[i], j = l[i] = i; j; j = l[j]-1){
                v[j] = fun(v[j], a[i]);
                while(l[j] > 1&&fun(a[i], v[l[j]-1]) == fun(a[i], v[j])) l[j] = l[l[j]-1];
                //[l[j]..j,i]区间内的值求fun均为v[j]
                if(last[ v[j] ]){
                    if(last[ v[j] ] < j){
                        add(last[ v[j] ], -1);
                        add(j, 1);
                        last[ v[j] ] = j;
                    }
                }
                else{//v[j] 没有
                    add(j, 1);
                    last[ v[j] ] = j;
                }
            }
            while(qq <= q&&query[qq].r == i){
                query[qq].ans = sum(query[qq].r) - sum(query[qq].l-1);
                qq++;
            }
        }
        sort(query+1, query+q+1, cmp2);
        for(int i = 1; i <= q; i++)
            printf("%d
", query[i].ans);
    }
}