Author: lllyouo
Date: 20251014
tag: 线段树
link: https://www.luogu.com.cn/problem/P1198

问题描述

link

分析

略

参考代码

#include <bits/stdc++.h>
using namespace std;

const int N = 2e5 + 10;
int m, d, n, t;

struct SegmentTree {
    int l, r, v;

} tr[4 * N];

void pushup(int p) {
    tr[p].v = max(tr[p << 1].v, tr[p << 1 | 1].v);
}

void build(int p, int l, int r) {
    tr[p].l = l, tr[p].r = r;
    if (l == r) {
        tr[p].v = -1e9;
        return;
    }

    int mid = (l + r) >> 1;
    build(p << 1, l, mid);
    build(p << 1 | 1, mid + 1, r);
    pushup(p);
}

void modify(int p, int x, int v) {
    if (tr[p].l == x && tr[p].r == x)
        tr[p].v = v;
    else {
        int mid = (tr[p].l + tr[p].r) >> 1;
        if (x <= mid)
            modify(p << 1, x, v);
        else
            modify(p << 1 | 1, x, v);
        pushup(p);
    }
}

int query(int p, int l, int r) {
    if (l <= tr[p].l && tr[p].r <= r) return tr[p].v;

    int mid = (tr[p].l + tr[p].r) >> 1, v = -1e9;
    if (l <= mid) v = max(v, query(p << 1, l, r));
    if (r > mid) v = max(v, query(p << 1 | 1, l, r));

    return v;
}

int main() {
    cin >> m >> d;

    build(1, 1, m);

    while (m--) {
        char op[2];
        int x;
        cin >> op >> x;

        if (op[0] == 'A') {
            modify(1, n + 1, ((long long)t + x) % d);
            n++;
        } else {
            t = query(1, n - x + 1, n);
            cout << t << endl;
        }
    }

    return 0;
}