python/TangDou/AcWing/SegmentTree/248_2.cpp

#include <iostream>
#include <algorithm>
#include <cmath>
#include <cstring>
#include <vector>

using namespace std;
typedef long long LL;
const int N = 10010;

struct Seg {
    LL x, y1, y2, c;
    bool operator<(const Seg &t) const {
        if (x == t.x) return c < t.c; //-1在前，1在后，先处理出边再处理入边
        return x < t.x;
    }
} seg[N << 1];

struct Node {
    int l, r;
    int maxc, add;
} tr[N << 3];

int n, w, h;
vector<LL> ys;

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

void build(int u, int l, int r) {
    tr[u] = {l, r, 0, 0};
    if (l == r) return;
    int mid = (l + r) >> 1;
    build(u << 1, l, mid);
    build(u << 1 | 1, mid + 1, r);
}

void pushdown(int u) {
    if (tr[u].add) {
        tr[u << 1].add += tr[u].add;
        tr[u << 1].maxc += tr[u].add;
        tr[u << 1 | 1].add += tr[u].add;
        tr[u << 1 | 1].maxc = tr[u << 1 | 1].maxc + tr[u].add;
        tr[u].add = 0;
    }
}

void modify(int u, int l, int r, int c) {
    if (l <= tr[u].l && tr[u].r <= r) {
        tr[u].maxc += c;
        tr[u].add += c;
        return;
    }

    pushdown(u);
    int mid = tr[u].l + tr[u].r >> 1;
    if (l <= mid) modify(u << 1, l, r, c);
    if (r > mid) modify(u << 1 | 1, l, r, c);

    pushup(u);
}

int find(LL x) {
    return lower_bound(ys.begin(), ys.end(), x) - ys.begin();
}

int main() {
    //加快读入
    cin.tie(0), ios::sync_with_stdio(false);

    while (cin >> n >> w >> h) {
        for (int i = 1; i <= n; i++) {
            LL x, y;
            int c;
            cin >> x >> y >> c;
            //区别在这里！
            /*
            需配合：
            if (x == t.x) return c < t.c; //-1在前，1在后，先处理出边再处理入边
            */
            seg[2 * i - 1] = {x, y, y + h - 1, c};
            seg[2 * i] = {x + w, y, y + h - 1, -c};
            ys.push_back(y), ys.push_back(y + h - 1);
        }

        sort(ys.begin(), ys.end());
        ys.erase(unique(ys.begin(), ys.end()), ys.end());

        sort(seg + 1, seg + 1 + 2 * n);

        build(1, 0, ys.size() - 1);

        int res = 0;
        for (int i = 1; i <= 2 * n; i++) {
            res = max(res, tr[1].maxc);
            modify(1, find(seg[i].y1), find(seg[i].y2), seg[i].c);
        }
        printf("%d\n", res);
    }
    return 0;
}