Submission #1115806

#	Time	Username	Problem	Language	Result	Execution time	Memory
1115806		vjudge1	Toll (BOI17_toll)	C++17	100 / 100	204 ms	45056 KiB

toll

#include <bits/stdc++.h>
using namespace std;

#define int long long
#define pii pair <int, int>
#define fi first
#define se second
#define mp make_pair

const int NM = 50000, INF = 1e18;

struct matrix{
	int M, N, grid[5][5];
	void init(int x, int y, int val){
		M = x, N = y;
		for (int i = 0; i < M; i++)
			for (int j = 0; j < N; j++)
				grid[i][j] = val;
	}
	matrix operator * (matrix b){
		matrix a = *this;
		matrix c;
		c.init(a.M, b.N, +INF);
		for (int i = 0; i < c.M; i++)
			for (int j = 0; j < c.N; j++)
				for (int k = 0; k < a.N; k++)
					c.grid[i][j] = min(c.grid[i][j], a.grid[i][k]+b.grid[k][j]);
		return c;
	}
};

int K, N, M, O, nLayer;
map <pii, int> d;
matrix A[NM+5];
matrix st[4*NM+5];

int Layer(int a){
	return a/K;
}

int dist(int a, int b){
	if (a == b) return 0;
	if (d.count(mp(a, b)) == 0) return +INF;
	return d[mp(a, b)];
}

matrix iden(int k){
	matrix a;
	a.init(k, k, +INF);
	for (int i = 0; i < k; i++)
		a.grid[i][i] = 0;
	return a;
}

void build(int id, int l, int r){
	st[id].init(K, K, 0);
	if (l == r){
		st[id] = A[l];
		return;
	}
	int mid = (l+r)/2;
	build(2*id, l, mid);
	build(2*id+1, mid+1, r);
	st[id] = st[2*id]*st[2*id+1];
}

matrix get(int id, int l, int r, int u, int v){
	if (u > v || v < l || u > r) return iden(K);
	if (l >= u && r <= v) return st[id];
	int mid = (l+r)/2;
	return get(2*id, l, mid, u, v)*get(2*id+1, mid+1, r, u, v);
}

void solveQuery(int a, int b){
	if (Layer(a) >= Layer(b)){
		cout << "-1\n";
		return;
	}
	int l = Layer(a), r = Layer(b);
	matrix C; C.init(1, K, +INF);
	for (int i = 0; i < K; i++)
		C.grid[0][i] = dist(a, (l+1)*K+i);
	C = C*get(1, 0, nLayer-2, l+1, r-1);
	int ans = C.grid[0][b%K];
	if (ans >= +INF) ans = -1;
	cout << ans << "\n";
}

signed main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin >> K >> N >> M >> O;
	nLayer = N/K+1;
	for (int i = 0; i < nLayer; i++)
		A[i].init(K, K, +INF);
	while (M--){
		int a, b, t;
		cin >> a >> b >> t;
		d[mp(a, b)] = t;
		int k = Layer(a);
		A[k].grid[a%K][b%K] = t;
	}
	build(1, 0, nLayer-2);
	while (O--){
		int a, b;
		cin >> a >> b;
		solveQuery(a, b);
	}
	return 0;
}

• Subtask 1: 7 / 7
• Subtask 2: 10 / 10
• Subtask 3: 8 / 8
• Subtask 4: 31 / 31
• Subtask 5: 44 / 44