线段树(二)区间最值

区间最值

#include<cstdio>
#include<iostream>
#include<iostream>
using namespace std;
const int Maxn=100001;
#define mid (l+r)/2
#define lc o<<1
#define rc (o<<1)+1

struct node{int mi;}point[Maxn*4];

int t,n,x,y,a[Maxn];

int query(int l,int r,int o,int x,int y)
{
if(l==r)return point[o].mi;
if(x==l&&y==r) return point[o].mi;
else if(y<=mid) return query(l,mid,lc,x,y);
else if(x>mid) return query(mid+1,r,rc,x,y);
else return min(query(l,mid,lc,x,mid),query(mid+1,r,rc,mid+1,y));
}

void build(int l,int r,int o)
{
if(l==r){point[o].mi=a[l];return;}
build(l,mid,lc);
build(mid+1,r,rc);
point[o].mi=min(point[lc].mi,point[rc].mi);
return;
}

int main()
{
scanf("%d%d",&n,&t);
for(int i=1;i<=n;i++)scanf("%d",&a[i]);
build(1,n,1);
for(int i=1;i<=t;i++)
{
scanf("%d%d",&x,&y);
printf("%d ",query(1,n,1,x,y));
}
}