【POJ3264】Balanced Lineup

 

RMQ模板题

#include<cstdio>
#include<cstring>
using namespace std;
const int N=50001,M=30;
int n,q,h[N],minl[N][M],maxl[N][M];
int RMQ(int,int),min(int,int),max(int,int);
int main(){
    int l,r,tmp;
    scanf("%d %d",&n,&q);
    for (int i=1;i<=n;i++){
        scanf("%d",&tmp);
        minl[i][0]=maxl[i][0]=tmp;
    }
    for (int j=1;j<=20;j++)
        for (int i=1;i<=n;i++)
            if (i+(1<<j)-1<=n){
            minl[i][j]=min(minl[i][j-1],minl[i+(1<<(j-1))][j-1]);
            maxl[i][j]=max(maxl[i][j-1],maxl[i+(1<<(j-1))][j-1]);
        }
    for (int i=1;i<=q;i++){
        scanf("%d %d",&l,&r);
        printf("%d\n",RMQ(l,r));
    }
    return 0;
}
int min(int x,int y){
    return x<y?x:y;
}
int max(int x,int y){
    return x>y?x:y;
}
int RMQ(int l,int r){
    int k=0;
    while ((1<<(k+1)) <=r-l+1) k++;
    return max(maxl[l][k],maxl[r-(1<<k)+1][k])-min(minl[l][k],minl[r-(1<<k)+1][k]);
}