Balanced Lineup

 1 #include<cstdio>
 2 #include<cstring>
 3 using namespace std;
 4 const int N=50001,M=30;
 5 int n,q,h[N],minl[N][M],maxl[N][M];
 6 int RMQ(int,int),min(int,int),max(int,int);
 7 int main(){
 8     int l,r,tmp;
 9     scanf("%d %d",&n,&q);
10     for (int i=1;i<=n;i++){
11         scanf("%d",&tmp);
12         minl[i][0]=maxl[i][0]=tmp;
13     }
14     for (int j=1;(1<<j)<=n;j++)
15         for (int i=1;i+j-1<=n;i++){
16             minl[i][j]=min(minl[i][j-1],minl[i+(1<<(j-1))][j-1]);
17             maxl[i][j]=max(maxl[i][j-1],maxl[i+(1<<(j-1))][j-1]);
18         }
19     for (int i=1;i<=q;i++){
20         scanf("%d %d",&l,&r);
21         printf("%d\n",RMQ(l,r));
22     }
23     return 0;
24 }
25 int min(int x,int y){
26     return x<y?x:y;
27 }
28 int max(int x,int y){
29     return x>y?x:y;
30 }
31 int RMQ(int l,int r){
32     int k=0;
33     while ((1<<(k+1)) <=r-l+1) k++;
34     return max(maxl[l][k],maxl[r-(1<<k)+1][k])-min(minl[l][k],minl[r-(1<<k)+1][k]);
35 }