HDU 1823 二维线段树

最新推荐文章于 2022-01-16 21:31:17 发布

最新推荐文章于 2022-01-16 21:31:17 发布 · 144 阅读

文章标签：

#c/c++

本文介绍了一种使用二维线段树解决特定问题的方法。通过构建树套树的方式，第一维代表高度，第二维代表活泼值，有效地实现了区间更新与查询操作。

题意就不赘述了。

二维线段树，第一维是高度，第二维是活泼值，然后建立树套树。

/*
ID: CUGB-wwj
PROG:
LANG: C++
*/
#include <iostream>
#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <queue>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <cmath>
#include <ctime>
#define INF 2000000000
#define MAXN 105
#define MAXM 1005
#define L(x) x<<1
#define R(x) x<<1|1
#define eps 1e-4
using namespace std;
struct Sub
{
    int left, right;
    int mx;
    int mid(){ return (left + right) >> 1;}
};
struct node
{
    int left, right;
    Sub subtree[4 * MAXM];
    int mid(){ return (left + right) >> 1;}
}tree[4 * MAXN];
void make_subtree(int s, int e, int C, int F)
{
    tree[F].subtree[C].left = s;
    tree[F].subtree[C].right = e;
    tree[F].subtree[C].mx = -1;
    if(s == e) return;
    int mid = (s + e) >> 1;
    make_subtree(s, mid, L(C), F);
    make_subtree(mid + 1, e, R(C), F);
}
void make_tree(int s, int e, int C)
{
    tree[C].left = s;
    tree[C].right = e;
    make_subtree(0, 1000, 1, C);
    if(s == e) return;
    int mid = (s + e) >> 1;
    make_tree(s, mid, L(C));
    make_tree(mid + 1, e, R(C));
}
void up_sub(int C, int F)
{
    tree[F].subtree[C].mx = max(tree[F].subtree[L(C)].mx, tree[F].subtree[R(C)].mx);
}
void update_sub(int p, int v, int C, int F)
{
    if(tree[F].subtree[C].left == tree[F].subtree[C].right)
    {
        tree[F].subtree[C].mx = max(tree[F].subtree[C].mx, v);
        return;
    }
    int mid = tree[F].subtree[C].mid();
    if(p <= mid) update_sub(p, v, L(C), F);
    else update_sub(p, v, R(C), F);
    up_sub(C, F);
}
void update(int pa, int pb, int v, int C)
{
    update_sub(pb, v, 1, C);
    if(tree[C].left == tree[C].right) return;
    int mid = tree[C].mid();
    if(pa <= mid) update(pa, pb, v, L(C));
    else update(pa, pb, v, R(C));
}
int query_sub(int s, int e, int C, int F)
{
    if(tree[F].subtree[C].left >= s && tree[F].subtree[C].right <= e) return tree[F].subtree[C].mx;
    int mid = tree[F].subtree[C].mid();
    int ret = -1;
    if(s <= mid) ret = max(ret, query_sub(s, e, L(C), F));
    if(mid < e) ret = max(ret, query_sub(s, e, R(C), F));
    return ret;
}
int query(int s, int e, int s2, int e2, int C)
{
    if(tree[C].left >= s && tree[C].right <= e) return query_sub(s2, e2, 1, C);
    int mid = tree[C].mid();
    int ret = -1;
    if(s <= mid) ret = max(ret, query(s, e, s2, e2, L(C)));
    if(mid < e) ret = max(ret, query(s, e, s2, e2, R(C)));
    return ret;
}
int main()
{
    int T;
    char op[5];
    while(scanf("%d", &T) != EOF && T)
    {
        make_tree(100, 200, 1);
        while(T--)
        {
            scanf("%s", op);
            int h1, h2;
            double a1, a2, L;
            if(op[0] == 'I')
            {
                scanf("%d%lf%lf", &h1, &a1, &L);
                update(h1, (int)(a1 * 10 + eps), (int)(L * 10 + eps), 1);
            }
            else
            {
                scanf("%d%d%lf%lf", &h1, &h2, &a1, &a2);
                if(h1 > h2) swap(h1, h2);
                if(a1 > a2) swap(a1, a2);
                int ret = query(h1, h2, (int)(a1 * 10 + eps), (int)(a2 * 10 + eps), 1);
                if(ret < 0) puts("-1");
                else printf("%.1f\n", ret / 10.0);
            }
        }
    }
    return 0;
}