Submission #1102173

#	Time	Username	Problem	Language	Result	Execution time	Memory
1102173		RiverFlow	Two Antennas (JOI19_antennas)	C++14	100 / 100	635 ms	50476 KiB

antennas

#include <bits/stdc++.h>

#define nl "\n"
#define no "NO"
#define yes "YES"
#define fi first
#define se second
#define vec vector
#define task "main"
#define _mp make_pair
#define ii pair<int, int>
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define evoid(val) return void(std::cout << val)
#define FOR(i, a, b) for(int i = (a); i <= (b); ++i)
#define FOD(i, b, a) for(int i = (b); i >= (a); --i)
#define unq(x) sort(all(x)); x.resize(unique(all(x)) - x.begin())

using namespace std;

template<typename U, typename V> bool maxi(U &a, V b) {
    if (a < b) { a = b; return 1; } return 0;
}
template<typename U, typename V> bool mini(U &a, V b) {
    if (a > b) { a = b; return 1; } return 0;
}

const int N = (int)2e5 + 9;
const int mod = (int)1e9 + 7;

void prepare(); void main_code();

int main() {
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    const bool MULTITEST = 0; prepare();
    int num_test = 1; if (MULTITEST) cin >> num_test;
    while (num_test--) { main_code(); }
}

void prepare() {};

int a[N], b[N], h[N];

int ans[N];

const int INF = (int)1e9 + 7;

struct segment_tree {
    struct node {
        int res;
        int lzh;
        int mxh;
        node () {
            res = -1;
            mxh = 0;
            lzh = INF; // min truyen vao
        };
    };
    int n;
    vector<node> t;
    segment_tree () {};
    segment_tree (int _n) {
        n = _n;
        t.resize(4 * n + 7);
    };
    void push(int id) {
        int &h = t[id].lzh;
        node &a = t[id << 1], &b = t[id << 1 | 1];
        if (a.mxh != 0) mini(a.lzh, h);
        if (b.mxh != 0) mini(b.lzh, h);
        maxi(a.res, a.mxh - a.lzh);
        maxi(b.res, b.mxh - b.lzh);
        h = INF;
    }
    void reff(int id) {
        t[id].res = max(t[id << 1].res, t[id << 1 | 1].res);
        t[id].mxh = max(t[id << 1].mxh, t[id << 1 | 1].mxh);
    }
    void upd(int id, int l, int r, int p, int vx) {
        if (l == r) {
            if (vx == 1) {
                t[id].mxh = h[p];
            } else {
                t[id].mxh = 0;
            }
            return ;
        }
        if (t[id].lzh != INF) {
            push(id);
        }
        int m = (l + r) >> 1;
        if (p <= m)
            upd(id << 1, l, m, p, vx);
        else
            upd(id << 1 | 1, m + 1, r, p, vx);
        reff(id);
    }
    void upd(int p, int vx) {
        upd(1, 1, n, p, vx);
    }
    void update(int id, int l, int r, int u, int v, int val) {
        if (l > v or r < u) return ;
        if (l >= u and r <= v) {
            maxi(t[id].res, t[id].mxh - val);
            if (t[id].mxh > 0)
                mini(t[id].lzh, val);
            return ;
        }
        if (t[id].lzh != INF) {
            push(id);
        }
        int m = (l + r) >> 1;
        update(id << 1, l, m, u, v, val);
        update(id << 1 | 1, m + 1, r, u, v, val);
        reff(id);
    }
    void update(int l, int r, int val) {
        if (r <= 0) return ;
        l = max(l, 1);
        update(1, 1, n, l, r, val);
    }
    int get(int id, int l, int r, int u, int v) {
        if (l > v or r < u) return -1;
        if (l >= u and r <= v) return t[id].res;
        if (t[id].lzh != INF) push(id);
        int m = (l + r) >> 1;
        return max(get(id << 1, l, m, u, v),
                   get(id << 1 | 1, m + 1, r, u, v));
    }
    int get(int l, int r) {
        return get(1, 1, n, l, r);
    }
};

int l[N], r[N];
vector<int> ins[N], del[N], qr[N];

void main_code() {
    int n; cin >> n;
    for(int i = 1; i <= n; ++i) {
        cin >> h[i] >> a[i] >> b[i];
    }
    int q; cin >> q;
    for(int i = 1; i <= q; ++i) {
        cin >> l[i] >> r[i];
        ans[i] = -1;
    }
for(int it = 0; it < 2; ++it) {
    reverse(h + 1, h + n + 1);
    reverse(a + 1, a + n + 1);
    reverse(b + 1, b + n + 1);
    for(int i = 1; i <= q; ++i) {
        l[i] = n - l[i] + 1;
        r[i] = n - r[i] + 1;
        swap(l[i], r[i]);
    }
    for(int i = 1; i <= n; ++i) {
        ins[i].clear(), del[i].clear(), qr[i].clear();
    }
    for(int i = 1; i <= n; ++i) {
        ins[min(n + 1, i + a[i])].push_back(i);
        del[min(n + 1, i + b[i])].push_back(i);
    }
    for(int i = 1; i <= q; ++i) {
        qr[r[i]].push_back(i);
    }
    segment_tree st(n);
    for(int i = 1; i <= n; ++i) {
        for(int j : ins[i]) {
            st.upd(j, 1);
        }
        st.update(i - b[i], i - a[i], h[i]);
        for(int j : qr[i]) {
            maxi(ans[j], st.get(l[j], i));
        }
        for(int j : del[i]) {
            st.upd(j, -1);
        }
    }
}
    for(int i = 1; i <= q; ++i) {
        cout << ans[i] << nl;
    }
}


/*     Let the river flows naturally     */

Compilation message (stderr)

antennas.cpp: In function 'int main()':
antennas.cpp:36:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
antennas.cpp:37:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 2 / 2
• Subtask 2: 11 / 11
• Subtask 3: 22 / 22
• Subtask 4: 65 / 65