[ybtoj 高效进阶 4.3] [RMQ] 静态区间

题目

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解题思路

RMQ模板求区间最大公因数

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代码

#include<iostream>
#include<cstdio>
using namespace std;
int n,m,x,y,log[50020],f[50020][40];
int gcd(int x,int y)
{
	if (x%y==0) return y;
	   else return gcd(y,x%y);
}
int main()
{
	scanf("%d%d",&n,&m);
	log[0]=-1;
	for (int i=1;i<=n;i++)
	    log[i]=log[i>>1]+1;
	for (int i=1;i<=n;i++)
	    scanf("%d",&f[i][0]);
	for (int j=1;j<=log[n];j++)
	    for (int i=1;i+(1<<j)-1<=n;i++)
	        f[i][j]=gcd(f[i][j-1],f[i+(1<<(j-1))][j-1]);
    for (int i=1;i<=m;i++)
    {
    	scanf("%d%d",&x,&y);
    	int k=log[y-x+1];
    	printf("%d\n",gcd(f[x][k],f[y-(1<<k)+1][k])); 
	}
	return 0;
}