HDU 1698 区间更新求和_in the game of dota pudge鈥檚 meat hook is actually -优快云博客

本文链接：https://blog.youkuaiyun.com/H1deonbush/article/details/46402453

本文介绍了一种基于树状数组实现的区间更新与查询算法。该算法通过构建树状结构来高效处理区间内的数值更新及求和操作，特别适用于需要频繁进行区间更新和查询的应用场景。

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#include <iostream>
#include <cstdio>
using namespace std;
const int MAX = 100100;

struct Tree
{
    int l,r,mark;
}tree[MAX * 4];
void BuildTree(int root,int l,int r)
{
    tree[root].l = l;
    tree[root].r = r;
    tree[root].mark = 1;
    if(tree[root].l == tree[root].r)
        return ;
    int mid = (tree[root].l + tree[root].r) / 2;
    BuildTree(root << 1,l,mid);
    BuildTree(root << 1|1,mid + 1,r);
}
void Update(int root,int l,int r,int val)
{
    if(l <= tree[root].l && r >= tree[root].r)
    {
        tree[root].mark = val;
        return ;
    }
    if(tree[root].mark != -1)
    {
        tree[root << 1].mark = tree[root << 1|1].mark = tree[root].mark;
        tree[root].mark = -1;
    }
    int mid = (tree[root].l + tree[root].r) / 2;
    if(l <= mid) Update(root << 1,l,r,val);  
    if(r >  mid) Update(root << 1|1,l,r,val);
}
int Query(int root,int l,int r)
{
    if(tree[root].l == l && tree[root].r == r)
    {
        if(tree[root].mark != -1)
        {
            return (r - l + 1) *tree[root].mark;
        }
        else
        {
            int mid = (tree[root].l + tree[root].r) / 2;
            return Query(root << 1,l,mid) + Query(root << 1|1,mid + 1,r);
        }
    }
    int mid = (tree[root].l + tree[root].r) / 2;
    if(r <= mid)  return Query(root << 1,l,mid);
    else if(l >  mid) return Query(root << 1|1,mid + 1,r);
    else
    {
        return Query(root << 1,l,mid) + Query(root << 1|1,mid + 1,r);
    }
}
int main()
{
    int T,cas = 1;
    scanf("%d",&T);
    while(T--)
    {
        int n,m;
        scanf("%d",&n);
        BuildTree(1,1,n);
        scanf("%d",&m);
        while(m--)
        {
            int L,R,change;
            scanf("%d%d%d",&L,&R,&change);
            Update(1,L,R,change);
        }
        printf("Case %d: The total value of the hook is %d.\n",cas,Query(1,1,n));
        cas ++;
    }
    return 0;
}