NC20164_JSOI2007最大数

NC20164.JSOI_2007_最大数

思路

这个题目需要维护两个信息 数组长度 和 区间最大值

因为是在线查询，所以不好用\(ST\)表，所以考虑线段树

因为\(M\)最多\(200000\),所以最多\(200000\)个数，开一个\(800000\)的数组足够了

用一个变量去维护数组长度就好了

代码

神奇的代码

#include <bits/stdc++.h>
#define endl '\n'
#define int long long
const int maxn = 2e5 + 5;
const int inf = 0x7f7f7f7f;

struct custom_hash 
{
	static uint64_t splitmix64(uint64_t x) 
    {
		x ^= x << 13;
		x ^= x >> 7;
		x ^= x << 17;
		return x; 
	}
	size_t operator () (uint64_t x) const 
    {
		static const uint64_t FIXED_RANDOM = std::chrono::steady_clock::now().time_since_epoch().count(); // 时间戳
		return splitmix64(x + FIXED_RANDOM);
	}
};
// 维护数组长度，区间最大值


int tree[4 * maxn];
int cur = 0;
int D = 0, M = 0, t = 0;
void update(int root)
{
    int ch = root << 1;
    tree[root] = std::max(tree[ch], tree[ch + 1]);
}

void modify(int root, int left, int right, int x, int pos)
{
    if (left == right)
    {
        tree[root] = x;
        return;
    }
    int ch = root << 1;
    int mid = (left + right) >> 1;
    if (pos <= mid)
    {
        modify(ch, left, mid, x, pos);
    }
    else
    {
        modify(ch + 1, mid + 1, right, x, pos);
    }
    update(root);
}

int query(int root, int left, int right, int x, int y)
{
    if (x <= left && right <= y)
    {
        return tree[root];
    }
    int ch = root << 1;
    int mid = (left + right) >> 1;
    if (y <= mid)
    {
        return query(ch, left, mid, x, y);
    }
    else if(x > mid)
    {
        return query(ch + 1, mid + 1, right, x, y);
    }
    else
    {
        return std::max(query(ch, left, mid, x, mid), query(ch + 1, mid + 1, right, mid + 1, y));
    }
}

void solve()
{
    std::cin >> M >> D;
    char f;
    int tmp = 0;
    while(M--)
    {
        std::cin >> f >> tmp;
        if (f == 'Q')
        {
            int l = cur - tmp + 1;
            t = query(1, 1, maxn, l, cur);
            std::cout << t << endl;
        }
        else
        {
            cur++;
            modify(1, 1, maxn, (tmp + t) % D, cur);
        }
    }
}

signed main()
{
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr); std::cout.tie(nullptr);
    //freopen("out.txt", "w", stdout);
    int t = 1;
    //std::cin >> t;
    while(t--)
    {
        solve();
    }
    return 0;
}