bzoj3381[Usaco2004 Open]Cave Cows 2 洞穴里的牛之二*

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 #define inc(i,j,k) for(int i=j;i<=k;i++)
 5 #define maxn 25100
 6 using namespace std;
 7 
 8 inline int read(){
 9     char ch=getchar(); int f=1,x=0;
10     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1; ch=getchar();}
11     while(ch>=‘0‘&&ch<=‘9‘)x=x*10+ch-‘0‘,ch=getchar();
12     return f*x;
13 }
14 int n,m,lg[maxn],mn[maxn][20];
15 int main(){
16     n=read(); m=read(); inc(i,1,n)mn[i][0]=read();
17     for(int i=0;1<<i<=n;i++)lg[1<<i]=i; inc(i,1,n)if(!lg[i])lg[i]=lg[i-1];
18     for(int i=1;1<<i<=n;i++)inc(j,1,n)if(j+(1<<i)-1<=n)mn[j][i]=min(mn[j][i-1],mn[j+(1<<(i-1))][i-1]);
19     inc(i,1,m){
20         int a=read(),b=read(),c=lg[b-a+1];
21         printf("%d\n",min(mn[a][c],mn[b-(1<<c)+1][c]));
22     }
23     return 0;
24 }