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Submission #497272

# Submission time Handle Problem Language Result Execution time Memory
497272 2021-12-22T22:19:57 Z SirCovidThe19th Link (CEOI06_link) C++17
92 / 100
 1500 ms 12412 KB 
#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 sz = nodes.size(), jmp[sz], bst = 2e9; 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 = sz * 2 - 1, pos = i % sz, lst = 2e9; ~i; i--, pos = i % sz){
        if (!ok[pos]) lst = pos;
        jmp[pos] = lst - i;
    }
    for (int st = 0; st < min(sz, k); st++){
        int trav = 0, tmp = 0;
        while (1){
            trav += jmp[(st + trav) % sz]; 
            if (trav >= sz) break;
            trav += k; tmp++;
        }
        bst = min(bst, tmp);
    }
    ans += bst;
}

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;
}

Subtask #1
92.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2252 KB Output is correct
2 Correct 1 ms 2252 KB Output is correct
3 Correct 2 ms 2252 KB Output is correct
4 Execution timed out 1579 ms 2236 KB Time limit exceeded
5 Execution timed out 1567 ms 2252 KB Time limit exceeded
6 Correct 17 ms 2820 KB Output is correct
7 Correct 31 ms 3268 KB Output is correct
8 Correct 39 ms 3768 KB Output is correct
9 Correct 58 ms 4636 KB Output is correct
10 Correct 73 ms 4520 KB Output is correct
11 Correct 85 ms 6588 KB Output is correct
12 Correct 110 ms 6576 KB Output is correct
13 Correct 163 ms 8172 KB Output is correct
14 Correct 189 ms 9276 KB Output is correct
15 Correct 207 ms 10736 KB Output is correct
16 Correct 269 ms 11448 KB Output is correct
17 Correct 295 ms 12100 KB Output is correct
18 Correct 319 ms 11964 KB Output is correct
19 Correct 332 ms 12076 KB Output is correct
20 Correct 363 ms 12080 KB Output is correct
21 Correct 326 ms 12104 KB Output is correct
22 Correct 436 ms 12180 KB Output is correct
23 Correct 331 ms 12008 KB Output is correct
24 Correct 322 ms 12224 KB Output is correct
25 Correct 338 ms 12412 KB Output is correct