Submission #375802

#	Time	Username	Problem	Language	Result	Execution time	Memory
375802		fhvirus	Two Antennas (JOI19_antennas)	C++17	13 / 100	136 ms	23552 KiB

antennas

// Knapsack DP is harder than FFT.
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii; typedef pair<ll, ll> pll;
#define ff first
#define ss second
#define pb emplace_back
#define FOR(i,n) for(int i = 0; i < (n); ++i)
#define FOO(i,a,b) for(int i = (a); i <= (b); ++i)
#define AI(x) begin(x),end(x)
template<typename I> bool chmax(I &a, I b){ return a < b ? ( a = b, true ) : false;}
template<typename I> bool chmin(I &a, I b){ return a > b ? ( a = b, true ) : false;}
#ifdef OWO
#define debug(args...) LKJ("[ " + string(#args) + " ]", args)
void LKJ(){cerr<<endl;}
template<class I, class...T> void LKJ(I&&x, T&&...t){ cerr<<x<<", ", LKJ(t...);}
template<class I> void DE(I a, I b){ while(a < b) cerr<<*a<<" \n"[next(a) == b], ++a;}
#else
#define debug(...) 0
#define DE(...) 0
#endif
const int N = 2002;
int n, q;
int h[N];
bool g[N][N];
int dp[N][N];
int32_t main(){
	ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
	cin >> n;

	assert(n < N);

	FOR(i,n){
		int l, r; cin >> h[i] >> l >> r;
		FOR(j,n){
			int d = abs(i - j);
			if(l <= d and d <= r) g[i][j] = true;
		}
	}

	FOR(i,n) FOO(j,i+1,n-1){
		if(!g[i][j] or !g[j][i]){
			dp[i][j] = dp[j][i] = -1;
			continue;
		}
		dp[i][j] = abs(h[i] - h[j]);
	}
	FOO(len,3,n){
		FOR(l,n){
			int r = l + len - 1;
			if(r >= n) continue;
			chmax(dp[l][r], dp[l+1][r]);
			chmax(dp[l][r], dp[l][r-1]);
		}
	}

	cin >> q;
	FOR(_,q){
		int l, r; cin >> l >> r;
		--l, --r;
		cout << dp[l][r] << '\n';
	}

	return 0;
}

• Subtask 1: 2 / 2
• Subtask 2: 11 / 11
• Subtask 3: 0 / 22
• Subtask 4: 0 / 65