[luogu1198][bzoj1012][JSOI2008]最大数【线段树+分块】

题目描述

区间查询最大值，结尾插入，强制在线。

分析

线段树可以做，但是练了一下分块，发现自己打错了两个地方，一个是分块的地方把/打成了%，还有是分块的时候标号要-1。
其他也没什么要多讲的。

代码

#include <bits/stdc++.h>
#define inf 0x3f3f3f3f
#pragma GCC optimize(2)
#define ll long long
#define linf 9223372036854775807
#define inf 0x3f3f3f3f
using namespace std;
template <typename T>
inline void read(T &x) {
    x = 0; T fl = 1;
    char ch = 0;
    while (ch < '0' || ch > '9') {
        if (ch == '-') fl = -1;
        ch = getchar();
    }
    while (ch >= '0' && ch <= '9') {
        x = (x << 1) + (x << 3) + (ch ^ 48);
        ch = getchar();
    }
    x *= fl;
}
ll mx[200005], a[200005];
int sum = 0, block, m, tot;
ll d, lst_ans = 0;
void insert(ll x, int n) {
    a[n] = x;
    if ((n - 1) % block == 0 || n == 1) mx[++ sum] = x;
    else mx[sum] = max(x, mx[sum]);
}
ll query(int l, int r) {
    int bl = (l - 1) / block + 1, br = (r - 1) / block + 1;
    ll res = -inf;
    if (bl == br) for (int i = l; i <= r; i ++) res = max(a[i], res);
    else {
        for (int i = l; i <= bl * block; i ++) res = max(res, a[i]);
        for (int i = br * block - block + 1; i <= r; i ++) res = max(res, a[i]);
        for (int i = bl + 1; i <= br - 1; i ++) res = max(res, mx[i]);
    }
    return res;
}
int main() {
//  freopen("data.in","r",stdin);
//  freopen("data.out","w",stdout);
    memset(mx, -inf, sizeof(mx));
    read(m); read(d);
    block = sqrt(m) / 2;
    tot = 0;
    for (int i = 1; i <= m; i ++) {
        char opt[3]; ll x;
        scanf("%s", opt);
        read(x);
        if (opt[0] == 'A') {
            x = ((x + lst_ans) % d + d) % d;
            insert(x, ++ tot);
        }
        else {
            lst_ans = query(tot - (int)x + 1, tot);
            printf("%lld\n", lst_ans);
        }
    }
    return 0;
}