이 제출은 이전 버전의 oj.uz에서 채점하였습니다. 현재는 제출 당시와는 다른 서버에서 채점을 하기 때문에, 다시 제출하면 결과가 달라질 수도 있습니다.
/**
Solution:
Idea: We can precompute for each node the sqrt(n) furthest nodes with a simple dp. Then for each query
if the number of forbidden nodes is less than sqrt(n) then for sure the answer will be among the precomputed
otherwise we can simply solve it with a brutefore since the queries of this type will be less than sqrt(n).
*/
#include <bits/stdc++.h>
const int32_t MAX_N = 1e5;
const int32_t BUCKET_SIZE = 300;
const int32_t INF = 2e9;
bool isInVector[MAX_N + 5];
bool isForbidden[MAX_N + 5];
std::vector< std::pair< int32_t, int32_t > > Merge(const std::vector< std::pair< int32_t, int32_t> > &v1,
const std::vector< std::pair< int32_t, int32_t > > &v2) {
std::vector< std::pair< int32_t, int32_t > > ans;
int32_t ind1 = 0, ind2 = 0;
while((ind1 < v1.size() || ind2 < v2.size()) && ans.size() < BUCKET_SIZE) {
if(ind1 < v1.size()) {
if(ind2 < v2.size()) {
if(v1[ind1].first >= v2[ind2].first + 1) {
if(!isInVector[v1[ind1].second]) {
isInVector[v1[ind1].second] = true;
ans.push_back(v1[ind1]);
}
ind1++;
}
else {
if(!isInVector[v2[ind2].second]) {
isInVector[v2[ind2].second] = true;
ans.push_back({ v2[ind2].first + 1, v2[ind2].second });
}
ind2++;
}
}
else {
if(!isInVector[v1[ind1].second]) {
isInVector[v1[ind1].second] = true;
ans.push_back(v1[ind1]);
}
ind1++;
}
}
else {
if(!isInVector[v2[ind2].second]) {
isInVector[v2[ind2].second] = true;
ans.push_back({ v2[ind2].first + 1, v2[ind2].second });
}
ind2++;
}
}
for(auto &x : ans) {
isInVector[x.second] = false;
}
return ans;
}
class Graph {
private:
struct Node {
int32_t id;
std::vector< std::pair< int32_t, int32_t > > dp;
std::vector< Node* > v;
};
int32_t cntNodes;
Node nodes[MAX_N + 5];
public:
void Init(int32_t _cntNodes) {
cntNodes = _cntNodes;
for(int32_t i = 1; i <= cntNodes; i++) {
nodes[i].id = i;
}
}
void AddEdge(int32_t from, int32_t to) {
nodes[from].v.push_back(&nodes[to]);
}
void Precompute() {
for(int32_t i = 1; i <= cntNodes; i++) {
std::vector< std::pair< int32_t, int32_t > > dists;
nodes[i].dp.push_back({ 0, i });
for(auto &x : nodes[i].v) {
nodes[i].dp = Merge(nodes[i].dp, x->dp);
}
}
}
int32_t SolveSmallK(int32_t t) {
for(auto &x : nodes[t].dp) {
if(!isForbidden[x.second]) {
return x.first;
}
}
return -1;
}
int32_t SolveBigK(int32_t t) {
std::vector< int32_t > dp(t + 1, 0);
for(int32_t i = 1; i <= t; i++) {
if(isForbidden[i]) {
dp[i] = -INF;
}
else {
dp[i] = 0;
}
for(auto &x : nodes[i].v) {
dp[i] = std::max(dp[i], dp[x->id] + 1);
}
}
return dp[t];
}
};
Graph g;
int main() {
std::ios_base::sync_with_stdio(false);
std::cin.tie(nullptr);
int32_t n, m, q;
std::cin >> n >> m >> q;
g.Init(n);
for(int32_t i = 0; i < m; i++) {
int32_t u, v;
std::cin >> u >> v;
g.AddEdge(v, u);
}
g.Precompute();
for(int32_t i = 0; i < q; i++) {
int32_t t, k;
std::cin >> t >> k;
std::vector< int32_t > c(k);
for(int32_t j = 0; j < k; j++) {
std::cin >> c[j];
isForbidden[c[j]] = true;
}
if(k >= BUCKET_SIZE) {
std::cout << g.SolveBigK(t) << '\n';
}
else {
std::cout << g.SolveSmallK(t) << '\n';
}
for(int32_t j = 0; j < k; j++) {
isForbidden[c[j]] = false;
}
}
}
컴파일 시 표준 에러 (stderr) 메시지
bitaro.cpp: In function 'std::vector<std::pair<int, int> > Merge(const std::vector<std::pair<int, int> >&, const std::vector<std::pair<int, int> >&)':
bitaro.cpp:21:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
while((ind1 < v1.size() || ind2 < v2.size()) && ans.size() < BUCKET_SIZE) {
~~~~~^~~~~~~~~~~
bitaro.cpp:21:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
while((ind1 < v1.size() || ind2 < v2.size()) && ans.size() < BUCKET_SIZE) {
~~~~~^~~~~~~~~~~
bitaro.cpp:22:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if(ind1 < v1.size()) {
~~~~~^~~~~~~~~~~
bitaro.cpp:23:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if(ind2 < v2.size()) {
~~~~~^~~~~~~~~~~
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