线段树模版（转）

Posted 2020-09-26 wzjhoutai

//===========================================
//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;
}