人生第一条线段树！！！！FLY 1427: RMQ 两数之间最小值

给N(1 <= N <= 250,000)个数, 和Q(0 <= Q <= 100,000)个询问, 对于每个询问求出所求两数之间(包括这两个数)的最小数.

共N行, 第i行: 第i个询问的答案

<pre name="code" class="cpp">#include<iostream>
#include<cstdio>
using namespace std;int a[250010];struct node
{int l,r,mid,Min;
}s[4*250010];
void build(int id,int l,int r)
{s[id].l=l;s[id].r=r;s[id].mid=(l+r)/2;if(l==r){s[id].Min=a[l];}else{build(id*2,l,s[id].mid);build(id*2+1,s[id].mid+1,r);s[id].Min=min(s[id*2].Min,s[id*2+1].Min);}
}int call(int id,int l,int r)
{if((l<=s[id].l)&&(r>=s[id].r)){return s[id].Min;}else if((l>s[id].mid)){return call(id*2+1,l,r);}else if(r<=s[id].mid){return call(id*2,l,r);}else{return min(call(id*2+1,l,r),call(id*2,l,r));}
}int main()
{int n;scanf("%d",&n);for(int i=1;i<=n;i++) scanf("%d",&a[i]);build(1,1,n);int s;int a,b;scanf("%d",&s);for(int i=1;i<=s;i++){scanf("%d %d",&a,&b);int t;if(a>b){t=a;a=b;b=t;}printf("%d\n",call(1,a,b));}return 0;}