#include <bits/stdc++.h>
using namespace std;
const int mx = 5e5 + 5;
int n, k, ans, indeg[mx], nxt[mx], dst[mx]; bool vis[mx];
void solveIndeg0(){
queue<int> q; memset(dst, 0x3f, sizeof(dst));
dst[1] = 0;
for (int i = 1; i <= n; i++) if (!indeg[i]) q.push(i);
while (!q.empty()){
int cur = q.front(), to = nxt[cur]; q.pop();
vis[cur] = 1;
if (dst[cur] > k) dst[cur] = 1, ans++;
dst[to] = min(dst[to], dst[cur] + 1);
if (!(--indeg[to])) q.push(to);
}
}
void solveCyc(int cur){
vector<int> nodes;
while (!vis[cur]) nodes.push_back(cur), vis[cur] = 1, cur = nxt[cur];
int stPos = 1e9, longest = -1, sz = nodes.size(); bool ok[sz] = {};
for (int i = 0, pos = i, D = 2e9; i < sz * 2; i++, pos = i % sz){
D = min(D + 1, dst[nodes[pos]]);
ok[pos] |= (D <= k);
}
for (int i = 0, pos = i, run = 0; i < sz * 2; i++, pos = i % sz){
if (!ok[pos] and run > longest) stPos = pos, longest = run;
run = (ok[pos] ? run + 1 : 0);
}
for (int i = stPos, pos = i, D = 2e9; i < sz * 2; i++, pos = i % sz){
if (!ok[pos]){
if (D > k) D = 1, ans++;
ok[pos] = 1;
}
D++;
}
}
int main(){
cin >> n >> k;
for (int i = 1; i <= n; i++){
int a, b; cin >> a >> b;
indeg[b]++; nxt[a] = b;
}
solveIndeg0();
for (int i = 1; i <= n; i++) if (!vis[i]) solveCyc(i);
cout<<ans<<endl;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
2220 KB |
Output is correct |
2 |
Correct |
1 ms |
2216 KB |
Output is correct |
3 |
Incorrect |
2 ms |
2252 KB |
Output isn't correct |
4 |
Correct |
2 ms |
2284 KB |
Output is correct |
5 |
Incorrect |
4 ms |
2252 KB |
Output isn't correct |
6 |
Incorrect |
17 ms |
2824 KB |
Output isn't correct |
7 |
Incorrect |
28 ms |
3108 KB |
Output isn't correct |
8 |
Incorrect |
39 ms |
3532 KB |
Output isn't correct |
9 |
Correct |
55 ms |
4260 KB |
Output is correct |
10 |
Correct |
55 ms |
4248 KB |
Output is correct |
11 |
Correct |
88 ms |
5336 KB |
Output is correct |
12 |
Correct |
127 ms |
5188 KB |
Output is correct |
13 |
Correct |
146 ms |
5932 KB |
Output is correct |
14 |
Incorrect |
218 ms |
6280 KB |
Output isn't correct |
15 |
Correct |
214 ms |
6964 KB |
Output is correct |
16 |
Correct |
236 ms |
7344 KB |
Output is correct |
17 |
Incorrect |
282 ms |
8116 KB |
Output isn't correct |
18 |
Incorrect |
296 ms |
8096 KB |
Output isn't correct |
19 |
Incorrect |
312 ms |
8156 KB |
Output isn't correct |
20 |
Incorrect |
299 ms |
8036 KB |
Output isn't correct |
21 |
Incorrect |
361 ms |
8212 KB |
Output isn't correct |
22 |
Incorrect |
303 ms |
8460 KB |
Output isn't correct |
23 |
Correct |
319 ms |
8268 KB |
Output is correct |
24 |
Correct |
309 ms |
8436 KB |
Output is correct |
25 |
Incorrect |
317 ms |
8364 KB |
Output isn't correct |