題目連結

#include<cstdio>
#include<algorithm>
#include<cmath>
using namespace std;
const int N=1e5+10;
inline int read()
{
	int x=0,f=0;char ch=getchar();
	while(ch<'0'||ch>'9')f|=ch=='-',ch=getchar();
	while(ch>='0'&&ch<='9')x=(x<<1)+(x<<3)+(ch^48),ch=getchar();
	if(f)x=-x;return x;
}
inline void write(int x)
{
	int buf[40],p=0;
	if(x<0)putchar('-'),x=-x;
	do{
		buf[p++]=x%10;x/=10;
	}while(x);
	for(int i=p-1;i+1;--i)putchar(buf[i]+48);
	putchar('\n');
}
int n,m,a[N],f[N][20];
int main()
{
	//freopen("in.txt","r",stdin);
    n=read();m=read();
    for(int i=1;i<=n;++i)
        a[i]=read();
    for(int i=1;i<=n;++i)
        f[i][0]=a[i];
    for(int j=1;j<20;++j)
        for(int i=1;i<=n-(1<<(j-1));i++)
            f[i][j]=max(f[i][j-1],f[i+(1<<(j-1))][j-1]);
    for(int i=1,l,r;i<=m;++i)
    {
    	l=read();r=read();
    	int k=log2(r-l+1);
    	write(max(f[l][k],f[r-(1<<k)+1][k]));
	}
	return 0;
}
 

總結

ST表模板