#include <bits/stdc++.h> using namespace std; const int MAXN = 500005; const int MAXK = 20005; int A[MAXN], B[MAXN]; int ed[MAXN], ind[MAXN]; bool chk[MAXN], on[MAXN], cyc[MAXN]; vector<int> cnod[MAXN]; int cn; queue<int> indz; void searchgraph(int x) { //printf("searchgraph(%d)\n", x); chk[x] = on[x] = true; if(on[ed[x]]) { for(int t = x; !cyc[t]; t = ed[t]) { cyc[t] = true; cnod[cn].push_back(t); } cn++; } else if(!chk[ed[x]]) searchgraph(ed[x]); on[x] = false; } void movek(int x, int k) { for(; k-- >= 0; x = ed[x]) chk[x] = true; if(--ind[x] == 0) indz.push(x); } int main() { ios::sync_with_stdio(0); cin.tie(0); int N, K; int ans = 0; cin >> N >> K; for(int i = 0; i < N; i++) cin >> A[i] >> B[i]; for(int i = 0; i < N; i++) { ed[A[i]] = B[i]; ind[B[i]]++; } for(int i = 1; i <= N; i++) if(!chk[i]) searchgraph(i); //printf("cn = %d\n", cn); //for(auto a : cnod[0]) printf("%d ", a); //printf("\n"); for(int i = 1; i <= N; i++) chk[i] = false; movek(1, K); for(int i = 1; i <= N; i++) if(ind[i] == 0) indz.push(i); while(!indz.empty()) { if(!chk[indz.front()] && !cyc[indz.front()]) { //printf("indz = %d\n", indz.front()); movek(indz.front(), K - 1); ans++; } indz.pop(); } //for(int i = 1; i <= N; i++) printf("%d ", int(chk[i])); //printf("\nans = %d\n", ans); for(int i = 0; i < cn; i++) { //for(auto a : cnod[i]) printf("%d ", a); //printf("\n"); bool done = true; for(auto a : cnod[i]) done &= chk[a]; if(done) continue; if(cnod[i].size() <= K) { ans++; continue; } int mn = cnod[i].size(); for(int j = 0; j < cnod[i].size(); j++) { int cnt = 0, t = j; while(t < cnod[i].size() + j) { while(t < cnod[i].size() + j && chk[cnod[i][t % cnod[i].size()]]) t++; if(t == cnod[i].size() + j) break; cnt++; t += K; } mn = min(mn, cnt); } ans += mn; } cout << ans; return 0; }

link.cpp: In function 'int main()':
link.cpp:70:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(cnod[i].size() <= K) {
      ~~~~~~~~~~~~~~~^~~~
link.cpp:75:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j = 0; j < cnod[i].size(); j++) {
                  ~~^~~~~~~~~~~~~~~~
link.cpp:77:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    while(t < cnod[i].size() + j) {
          ~~^~~~~~~~~~~~~~~~~~~~
link.cpp:78:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while(t < cnod[i].size() + j && chk[cnod[i][t % cnod[i].size()]]) t++;
           ~~^~~~~~~~~~~~~~~~~~~~
link.cpp:79:10: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if(t == cnod[i].size() + j) break;
        ~~^~~~~~~~~~~~~~~~~~~~~