ST表模板题

竟然用了快读 逃

#include<cstdio>
#include<algorithm>
using namespace std;
#define maxn 200005
#define maxm 21
int f[maxn][maxm];
int logn[maxn];
int n,m;
void pre() {
	logn[1]=0;
	logn[2]=1;
	for(int i=3; i<maxn; i++)
		logn[i]=logn[i>>1]+1;
}
int read() {
	int x=0,f=1;
	char ch=getchar();
	while (ch<'0'||ch>'9') {
		if (ch=='-') f=-1;
		ch=getchar();
	}
	while (ch>='0'&&ch<='9') {
		x=x*10+ch-48;
		ch=getchar();
	}
	return x*f;
}
int x,y;
int main() {
	n=read();
	m=read();
	pre();
	for(int i=1; i<=n; i++)f[i][0]=read();
	for (int j = 1; j < maxm; 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]);
	for (int i = 1; i <= m; i++) {
		int x = read(), y = read();
		int s = logn[y - x + 1];
		printf("%d\n", max(f[x][s], f[y - (1 << s) + 1][s]));
	}
	return 0;
}