线段树模板（区间和最大值最下值）

//===========================================

//segment tree

//final version

//by kevin_samuel(fenice)苏州大学孙俊彦

#include <iostream>

#include <cstdio>

#include <cmath>





using namespace std;



#define MAXN 100

#define INF 0x3fffffff



int A[MAXN];

//int max;

//int min;



struct node

{

    int left;

    int right;

    int max;           //维护最大值

    int sum;          //维护区间和

    int min;           //维护最小值

}Tree[MAXN<<2];





void maintain(int root)         //向上调整

{

    int LC = root<<1;

    int RC = (root<<1)+1;

    Tree[root].sum = Tree[LC].sum + Tree[RC].sum;

    Tree[root].max = max(Tree[LC].max,Tree[RC].max);

    Tree[root].min = min(Tree[LC].min,Tree[RC].min);

}



void Build(int root,int start,int end)                     //构建线段树

{

    Tree[root].left = start;

    Tree[root].right = end;

    if(start == end)

    {

        Tree[root].sum = A[start];

        Tree[root].max = A[start];

        Tree[root].min = A[start];

        return;

    }

    int mid = (start + end)>>1;

    Build(root<<1,start,mid);

    Build((root<<1)+1,mid+1,end);

    maintain(root);

}



void update(int root,int pos,int value)                     //更新点的值

{

    if(Tree[root].left == Tree[root].right && Tree[root].left == pos)

    {

        Tree[root].sum += value;

        Tree[root].max += value;

        Tree[root].min += value;

        return;

    }

    int mid = (Tree[root].left + Tree[root].right)>>1;

    if(pos <= mid)

        update(root<<1,pos,value);

    else

        update((root<<1)+1,pos,value);

    maintain(root);

}



int Query(int root,int start,int end)                         //查询区间和

{

    if(start == Tree[root].left && Tree[root].right == end)

    {

        return Tree[root].sum;

    }

    int mid = (Tree[root].left + Tree[root].right)>>1;

    int ret = 0;

    if(end <= mid)

        ret += Query(root<<1,start,end);

    else if(start >= mid+1)

        ret += Query((root<<1)+1,start,end);

    else

    {

        ret += Query(root<<1,start,mid);

        ret += Query((root<<1)+1,mid+1,end);

    }

    return ret;

}



int RminQ(int root,int start,int end)              //查询区间最小值

{

    if(start == Tree[root].left && Tree[root].right == end)

    {

        return Tree[root].min;

    }

    int mid = (Tree[root].left + Tree[root].right)>>1;

    int ret = INF;

    if(end <= mid)

        ret = min(ret,RminQ(root<<1,start,end));

    else if(start >= mid+1)

        ret = min(ret,RminQ((root<<1)+1,start,end));

    else

    {

        int a = RminQ(root<<1,start,mid);

        int b = RminQ((root<<1)+1,mid+1,end);

        ret = min(a,b);

    }

    return ret;

}



int RmaxQ(int root,int start,int end)                 //查询区间最大值

{

    if(start == Tree[root].left && Tree[root].right == end)

    {

        return Tree[root].max;

    }

    int mid = (Tree[root].left + Tree[root].right)>>1;

    int ret = 0;    //modify this

    if(end <= mid)

        ret = max(ret,RmaxQ(root<<1,start,end));

    else if(start >= mid+1)

        ret = max(ret,RmaxQ((root<<1)+1,start,end));

    else

    {

        int a = RmaxQ(root<<1,start,mid);

        int b = RmaxQ((root<<1)+1,mid+1,end);

        ret = max(a,b);

    }

    return ret;

}



int main()

{

    return 0;

}