题目1544：数字序列区间最小值

#include<stdio.h>
#include<math.h>
const int k=17;// 2^16<10^5<2^17
int a[100001];
int f[100001][20];
int n;
int min(int a,int b)
{
    return(a<b?a:b);
}
int rmq()
{
    for (int i=1;i<=n;i++) //初始化
        f[i][0]=a[i];
    for (int j=1;j<k;j++)
        for (int i=1;i<=n;i++)
            if (i+(1<<j)-1<=n)   //通过位运算1<<j表示2^j;
                f[i][j]=min(f[i][j-1],f[i+(1<<j-1)][j-1]);
    return 0;
}
int query(int l,int r)
{
    int k=(int)(log((double)(r-l+1))/log(2.0));
    return(min(f[l][k],f[r-(1<<k)+1][k]));
}
int main()
{
    while (scanf("%d",&n)!=EOF)
    {
        for (int i=1;i<=n;i++)
            scanf("%d",&a[i]);
        rmq();
        int t;
        scanf("%d",&t);
        for (int i=0;i<t;i++)
        {
            int l,r;
            scanf("%d%d",&l,&r);
            printf("%d\n",query(l,r));
        }
    }
    return 0;
}