Nice triplets

input/code.cpp: In function 'void cc(int)':
input/code.cpp:15:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i=0; i<rt[c].size(); ++i){
                              ^
input/code.cpp: In function 'void cy(int)':
input/code.cpp:26:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i=0; i<rt[c].size(); ++i){
                              ^
input/code.cpp: In function 'long long int gets(int, int)':
input/code.cpp:39:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i=0; i<rt[c].size(); ++i){
                              ^
input/code.cpp:51:30: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i=1; i<getsv.size(); ++i){
                              ^

#include <iostream>
#include <vector>
using namespace std;
int n;

vector<int> rt[4040];

int aid[4040][4040];
int yid[4040][4040];

int u[4040];

void cc(int c){
  aid[c][0]=1;
  for (int i=0; i<rt[c].size(); ++i){
    int w=rt[c][i];
    if (u[c]==w) continue;
    u[w]=c;
    cc(w);
    ++aid[c][1];
    for (int i=1; i<4040; ++i) aid[c][i+1]+=aid[w][i];
  }
}

void cy(int c){
  for (int i=0; i<rt[c].size(); ++i){
    int w=rt[c][i];
    if (u[c]==w) continue;
    yid[w][1]=1;
    for (int i=1; i<4040; ++i) yid[w][i+1]+=(aid[c][i]+yid[c][i]-aid[w][i-1]);
    cy(w);
  }  
}

vector<long long> getsv;
long long dp[4040][4];
long long gets(int c, int d){
  getsv.clear();
  for (int i=0; i<rt[c].size(); ++i){
    int w=rt[c][i];
    if (w==u[c]) continue;
    if (aid[w][d-1]) getsv.push_back(aid[w][d-1]);
  }
  if (yid[c][d]) getsv.push_back(yid[c][d]);
  if (getsv.size()<3) return 0;
//   cout << "getsv: ";
//   for (int i=0; i<getsv.size(); ++i) cout << getsv[i] << " ";
//   cout << endl;
  dp[0][0]=1;
  dp[0][1]=getsv[0];
  for (int i=1; i<getsv.size(); ++i){
    dp[i][0]=1;
    dp[i][1]=dp[i-1][1]+getsv[i];
    dp[i][2]=dp[i-1][2]+dp[i-1][1]*getsv[i];
    dp[i][3]=dp[i-1][3]+dp[i-1][2]*getsv[i];
  }
//   cout << "gets(" << c << ", " << d << ")=" <<  dp[getsv.size()-1][3] << "\n";
  return dp[getsv.size()-1][3];
}


int main(){
  cin >> n;
  for (int i=1; i<n; ++i){
    int a, b;
    cin >> a >> b;
    rt[a].push_back(b);
    rt[b].push_back(a);
  }
  cc(1);
  cy(1);
  for (int d=1; d<n; ++d){
//     cout << "d-nice-d: " << d << endl;
    long long ans=0;
    if (d%2==0){
      for (int i=1; i<=n; ++i){
	ans+=gets(i, d/2);
      }
    }
   cout << ans << " ";
  }cout << "\n";
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: ACCEPTED

Test 27

Verdict: ACCEPTED

Test 28

Verdict: ACCEPTED

Test 29

Verdict: ACCEPTED

Test 30

Verdict: ACCEPTED

Test 31

Verdict: ACCEPTED

Test 32

Verdict: ACCEPTED

Test 33

Verdict: ACCEPTED

Test 34

Verdict: ACCEPTED

Test 35

Verdict: ACCEPTED

Test 36

Verdict: ACCEPTED

Test 37

Verdict: ACCEPTED

Test 38

Verdict: ACCEPTED

Test 39

Verdict: ACCEPTED

Test 40

Verdict: ACCEPTED