题意 给出一个序列 每次查询区间的max-min是多少
思路：直接维护max 和min即可 写两个query分别查最大最小值
1 #include<cstdio> 2 #include<algorithm> 3 #include<set> 4 #include<vector> 5 #include<cstring> 6 #include<iostream> 7 using namespace std; 8 const int maxn=5e4+5; 9 int a[maxn]; 10 struct Node{ 11 int l,r,maxnum,minnum; 12 }tree[maxn*4]; 13 void push_up(int x){ 14 tree[x].maxnum=max(tree[x<<1].maxnum,tree[x<<1|1].maxnum); 15 tree[x].minnum=min(tree[x<<1].minnum,tree[x<<1|1].minnum); 16 } 17 int query1(int x,int l,int r){ 18 int L=tree[x].l,R=tree[x].r; 19 if(l<=L&&R<=r){ 20 return tree[x].maxnum; 21 } 22 else { 23 int mid=L+R>>1; 24 int ans=0; 25 if(l<=mid)ans=max(ans,query1(x<<1,l,r)); 26 if(mid<r)ans=max(ans,query1(x<<1|1,l,r)); 27 return ans; 28 } 29 } 30 int query2(int x,int l,int r){ 31 int L=tree[x].l,R=tree[x].r; 32 if(l<=L&&R<=r){ 33 return tree[x].minnum; 34 } 35 else { 36 int mid=L+R>>1; 37 int ans=1e7; 38 if(l<=mid)ans=min(ans,query2(x<<1,l,r)); 39 if(mid<r)ans=min(ans,query2(x<<1|1,l,r)); 40 return ans; 41 } 42 } 43 void build(int x,int l,int r){ 44 tree[x].l=l,tree[x].r=r; 45 if(l==r){ 46 tree[x].maxnum=tree[x].minnum=a[l]; 47 } 48 else { 49 int mid=l+r>>1; 50 build(x<<1,l,mid); 51 build(x<<1|1,mid+1,r); 52 push_up(x); 53 } 54 } 55 int main(){ 56 int n,q; 57 scanf("%d%d",&n,&q); 58 for(int i=1;i<=n;i++)scanf("%d",&a[i]); 59 build(1,1,n); 60 for(int i=1;i<=q;i++){ 61 int x,y; 62 scanf("%d%d",&x,&y); 63 printf("%d ",query1(1,x,y)-query2(1,x,y)); 64 } 65 return 0; 66 }