Submission #743843

#	Time	Username	Problem	Language	Result	Execution time	Memory
743843		nguyentunglam	Two Antennas (JOI19_antennas)	C++17	100 / 100	597 ms	38196 KiB

antennas

#include<bits/stdc++.h>
#define fi first
#define se second
#define endl "\n"
#define ii pair<int, int>
using namespace std;
const int N = 2e5 + 10;
int h[N], a[N], b[N], T[N << 2], mx[N << 2], mn[N << 2], ans[N];
vector<ii> query[N], event[N];
int n;
void push(int s, int l, int r) {
    T[s] = max(T[s], mx[s] - mn[s]);
    if (l != r) {
        mx[s << 1] = max(mx[s << 1], mx[s]);
        mx[s << 1 | 1] = max(mx[s << 1 | 1], mx[s]);
    }
    mx[s] = 0;
}
void upval (int s, int l, int r, int pos, int val) {
    push(s, l, r);
    if (l == r) {
        mn[s] = val;
        return;
    }
    int mid = l + r >> 1;
    if (pos <= mid) upval(s << 1, l, mid, pos, val);
    else upval(s << 1 | 1, mid + 1, r, pos, val);
    mn[s] = min(mn[s << 1], mn[s << 1 | 1]);
}
void upans (int s, int l, int r, int from, int to, int val) {
    push(s, l, r);
    if (l > to || r < from) return;
    if (from <= l && r <= to) {
        mx[s] = val;
        push(s, l, r);
        return;
    }
    int mid = l + r >> 1;
    upans(s << 1, l, mid, from, to, val);
    upans(s << 1 | 1, mid + 1, r, from, to, val);
    T[s] = max(T[s << 1], T[s << 1 | 1]);
}
int get(int s, int l, int r, int from, int to) {
    push(s, l, r);
    if (l > to || r < from) return -1;
    if (from <= l && r <= to) return T[s];
    int mid = l + r >> 1;
    return max(get(s << 1, l, mid, from, to), get(s << 1 | 1, mid + 1, r, from, to));
}
void solve() {
    for(int i = 1; i <= 4 * n; i++) T[i] = -1, mx[i] = 0, mn[i] = 1e9;

    for(int i = 1; i <= n; i++) {
        if (i + a[i] <= n) event[i + a[i]].emplace_back(i, h[i]);
        if (i + b[i] + 1 <= n) event[i + b[i] + 1].emplace_back(i, 1e9);
    }
    for(int r = 1; r <= n; r++) {
        for(auto &[pos, val] : event[r]) upval(1, 1, n, pos, val);
        upans(1, 1, n, r - b[r], r - a[r], h[r]);
        for(auto &[l, idx] : query[r]) ans[idx] = max(ans[idx], get(1, 1, n, l, n));
        event[r].clear();
    }
}
int main() {
    #define task ""
    cin.tie(0) -> sync_with_stdio(0);
    if (fopen ("task.inp", "r")) {
        freopen ("task.inp", "r", stdin);
        freopen ("task.out", "w", stdout);
    }
    if (fopen (task".inp", "r")) {
        freopen (task".inp", "r", stdin);
        freopen (task".out", "w", stdout);
    }
    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++) {
        int l, r; cin >> l >> r;
        query[r].emplace_back(l, i);
        ans[i] = -1;
    }
    solve();
    for(int i = 1; i <= n; i++) h[i] = 1e9 - h[i];
    solve();
    for(int i = 1; i <= q; i++) cout << ans[i] << endl;
}

Compilation message (stderr)

antennas.cpp: In function 'void upval(int, int, int, int, int)':
antennas.cpp:25:17: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   25 |     int mid = l + r >> 1;
      |               ~~^~~
antennas.cpp: In function 'void upans(int, int, int, int, int, int)':
antennas.cpp:38:17: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   38 |     int mid = l + r >> 1;
      |               ~~^~~
antennas.cpp: In function 'int get(int, int, int, int, int)':
antennas.cpp:47:17: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   47 |     int mid = l + r >> 1;
      |               ~~^~~
antennas.cpp: In function 'int main()':
antennas.cpp:68:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   68 |         freopen ("task.inp", "r", stdin);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
antennas.cpp:69:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   69 |         freopen ("task.out", "w", stdout);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
antennas.cpp:72:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |         freopen (task".inp", "r", stdin);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
antennas.cpp:73:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   73 |         freopen (task".out", "w", stdout);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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