bzoj 3381: [Usaco2004 Open]Cave Cows 2 洞穴里的牛之二

→题目链接←

裸线段树

查询最小值

代码：

#include<iostream>#include<cstdio>#include<algorithm>using namespace std;struct node{int l,r,Min;}tree[30000*4];void build(int num,int l,int r){tree[num].l=l;tree[num].r=r;if(l==r){scanf("%d",&tree[num].Min);return;}int mid=(l+r)/2;build(num*2,l,mid);build(num*2+1,mid+1,r);tree[num].Min=min(tree[num*2].Min,tree[num*2+1].Min);}int query(int num,int l,int r){if(tree[num].l>=l && tree[num].r<=r)return tree[num].Min;int mid=(tree[num].l+tree[num].r)/2;if(r<=mid)return query(num*2,l,r);else if(l>mid)return query(num*2+1,l,r);else return min(query(num*2,l,mid),query(num*2+1,mid+1,r));}int n,m;int main(){scanf("%d%d",&n,&m);build(1,1,n);for(int i=0; i<m; i++){int x,y;scanf("%d%d",&x,&y);printf("%d\n",query(1,x,y));}return 0;}