Submission #510277

#	Time	Username	Problem	Language	Result	Execution time	Memory
510277		couplefire	Two Antennas (JOI19_antennas)	C++17	100 / 100	757 ms	66076 KiB

antennas

#include<stdio.h>
#include<vector>
#include<algorithm>
 
using namespace std;
 
#define MAXN 200005
 
const int INF = 1 << 30;
int N, Q;
int H[MAXN], A[MAXN], B[MAXN], L[MAXN], R[MAXN];
int ans[MAXN];
int minc[4*MAXN], maxd[4*MAXN], lazy[4*MAXN];
vector<int> query[MAXN], on[2*MAXN], off[2*MAXN];
 
void spreadlazy(int idx) {
	lazy[idx * 2] = max(lazy[idx * 2], lazy[idx]);
	lazy[idx * 2 + 1] = max(lazy[idx * 2 + 1], lazy[idx]);
	maxd[idx * 2] = max(maxd[idx * 2], lazy[idx * 2] - minc[idx * 2]);
	maxd[idx * 2 + 1] = max(maxd[idx * 2 + 1], lazy[idx * 2 + 1] - minc[idx * 2 + 1]);
	lazy[idx] = -1;
}
 
void updc(int idx, int l, int r, int x, int c) {
	if(l == r) {
		minc[idx] = c;
		lazy[idx] = -1;
		return;
	}
	spreadlazy(idx);
	int m = (l + r) / 2;
	if(x <= m) updc(idx * 2, l, m, x, c);
	else updc(idx * 2 + 1, m + 1, r, x, c);
	minc[idx] = min(minc[idx * 2], minc[idx * 2 + 1]);
	maxd[idx] = max(maxd[idx * 2], maxd[idx * 2 + 1]);
}
 
void updlazy(int idx, int l, int r, int x, int y, int z) {
	if(x <= l && r <= y) {
		lazy[idx] = max(lazy[idx], z);
		maxd[idx] = max(maxd[idx], lazy[idx] - minc[idx]);
		return;
	}
	if(r < x || y < l) return;
	spreadlazy(idx);
	int m = (l + r) / 2;
	updlazy(idx * 2, l, m, x, y, z);
	updlazy(idx * 2 + 1, m + 1, r, x, y, z);
	maxd[idx] = max(maxd[idx * 2], maxd[idx * 2 + 1]);
}
 
int gmaxd(int idx, int l, int r, int x, int y) {
	if(x <= l && r <= y) return maxd[idx];
	if(r < x || y < l) return -1;
	int m = (l + r) / 2;
	spreadlazy(idx);
	return max(gmaxd(idx * 2, l, m, x, y), gmaxd(idx * 2 + 1, m + 1, r, x, y));
}
 
void solve() {
	for(int i = 0; i < N; i++) {
		query[i].clear();
		on[i].clear();
		off[i].clear();
	}
	
	for(int i = 0; i < Q; i++) query[R[i]].push_back(i);
	for(int i = 0; i < N; i++) {
		on[i + A[i]].push_back(i);
		off[i + B[i]].push_back(i);
	}
	for(int i = 1; i < 4 * N; i++) {
		minc[i] = INF;
		maxd[i] = lazy[i] = -1;
	}
 
	for(int i = 0; i < N; i++) {
		for(auto a : on[i]) updc(1, 0, N-1, a, H[a]);
		updlazy(1, 0, N-1, i - B[i], i - A[i], H[i]);
		for(auto a : query[i]) ans[a] = max(ans[a], gmaxd(1, 0, N-1, L[a], i));
		for(auto a : off[i]) updc(1, 0, N-1, a, INF);
	}
}
 
int main() {
	scanf("%d", &N);
	for(int i = 0; i < N; i++) scanf("%d%d%d", H+i, A+i, B+i);
	scanf("%d", &Q);
	for(int i = 0; i < Q; i++) scanf("%d%d", L+i, R+i);
 
	for(int i = 0; i < Q; i++) {
		ans[i] = -1;
		L[i]--;
		R[i]--;
	}
	solve();
	for(int i = 0; i < N/2; i++){
		swap(H[i], H[N - i - 1]);
		swap(A[i], A[N - i - 1]);
		swap(B[i], B[N - i - 1]);
	}
	for(int i = 0; i < Q; i++) {
		swap(L[i], R[i]);
		L[i] = N - L[i] - 1;
		R[i] = N - R[i] - 1;
	}
	solve();
 
	for(int i = 0; i < Q; i++) printf("%d\n", ans[i]);
	return 0;
}

Compilation message (stderr)

antennas.cpp: In function 'int main()':
antennas.cpp:86:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   86 |  scanf("%d", &N);
      |  ~~~~~^~~~~~~~~~
antennas.cpp:87:34: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   87 |  for(int i = 0; i < N; i++) scanf("%d%d%d", H+i, A+i, B+i);
      |                             ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
antennas.cpp:88:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   88 |  scanf("%d", &Q);
      |  ~~~~~^~~~~~~~~~
antennas.cpp:89:34: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   89 |  for(int i = 0; i < Q; i++) scanf("%d%d", L+i, R+i);
      |                             ~~~~~^~~~~~~~~~~~~~~~~~

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