题目
询问一个区间内最大值与最小值的差。
分析
RMQ
代码
#include <cstdio>
#include <cctype>
using namespace std;
int f[60101][17],f1[60101][17];
int max(int a,int b){return (a>b)?a:b;}
int min(int a,int b){return (a<b)?a:b;}
int in(){
int ans=0; char c=getchar();
while (!isdigit(c)) c=getchar();
while (isdigit(c)) ans=ans*10+c-48,c=getchar();
return ans;
}
int main(){
int n,q,x,y,z;
n=in(); q=in();
for (int i=1;i<=n;i++) f[i][0]=f1[i][0]=in();
for (int j=1;(1<<(j-1))<=n;j++)
for (int i=1;i+(1<<j)-1<=n;i++)
f[i][j]=max(f[i][j-1],f[i+(1<<(j-1))][j-1]),
f1[i][j]=min(f1[i][j-1],f1[i+(1<<(j-1))][j-1]);
for (int i=1;i<=q;i++){
x=in(); y=in(); z=0;
while ((1<<(z+1))<=y-x+1) z++;
printf("%d\n",max(f[x][z],f[y-(1<<z)+1][z])-min(f1[x][z],f1[y-(1<<z)+1][z]));
}
return 0;
}