Poj3264balanced lineup (Basic Line Segment tree)

Uses a one-dimensional array. (Because the one-dimensional number is a Complete Binary Tree, the time is slower than using the child node pointer to build the tree, but you can basically ignore =-=)

#include<iostream>#include<cstdio>#include<algorithm>using namespace std;const int INF = 0xffffff0;int minV=INF;int maxV=-INF;struct Node{    int L,R;    int minV,maxV;    int Mid()    {        return (L+R)/2;    }};Node tree[800010];void BuildTree(int root,int L,int R){    tree[root].L=L;    tree[root].R=R;    tree[root].maxV=-INF;    tree[root].minV=INF;    if(L!=R)    {        BuildTree(2*root+1,L,(L+R)/2);        BuildTree(2*root+2,1+(L+R)/2,R);    }}void Insert(int root, int i,int v){    if(tree[root].L==tree[root].R)    {        tree[root].maxV=tree[root].minV=v;        return;    }    tree[root].minV=min(tree[root].minV,v);    tree[root].maxV=max(tree[root].maxV,v);    if(i<=tree[root].Mid())    {        Insert(2*root+1,i,v);    }    else    {        Insert(2*root+2,i,v);    }}void Query(int root,int s,int e){    if(tree[root].minV>=minV&&tree[root].maxV<=maxV)    {        return;    }    if(tree[root].L==s&&tree[root].R==e)    {        minV=min(tree[root].minV,minV);        maxV=max(tree[root].maxV,maxV);        return;    }    if(e<=tree[root].Mid())    {        Query(1+root*2,s,e);    }    else if(s>tree[root].Mid())    {        Query(2+root*2,s,e);    }    else    {        Query(2*root+1,s,tree[root].Mid());        Query(2*root+2,tree[root].Mid()+1,e);    }}int main(){    int n,q,h;    int i;    //freopen("d:\\test.txt","r",stdin);    scanf("%d%d",&n,&q);    BuildTree(0,1,n);    for( i= 1; i <= n; i++ )    {        scanf("%d",&h);        Insert(0,i,h);    }    for( i= 0; i < q; i++ )    {        int s,e;        scanf("%d%d", &s,&e);        minV= INF;        maxV= -INF;        Query(0,s,e);        printf("%d\n",maxV-minV);    }    return 0;}

Poj3264balanced lineup (Basic Line Segment tree)