solved 18869

Author: atobaum

18000/18869/18869.cpp

@@ -0,0 +1,90 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+bool compare(vector<int> a, vector<int> b){
+	for(int i=0; i<a.size(); ++i){
+		if(a[i] > b[i]) return true;
+		else if(a[i] < b[i]) return false;
+	}
+
+	return false;
+}
+
+bool isEqual(vector<int> a, vector<int> b){
+	for(int i=0; i<a.size(); ++i){
+		if(a[i] != b[i]) return false;
+	}
+
+	return true;
+}
+
+int M, N, i, j, primes[10001]={2};
+vector<int> planets[100];
+
+bool isPrime(int n){
+	if(n==2) return true;
+	if(n%2==0) return false;
+
+	for(int i=3;i*i<=n;i+=2){
+		if(n%i==0) return false;
+	}
+
+	return true;
+}
+
+void fill_up_primes(){
+	int i = 0, cur = 3;
+	while(i < N){
+		if(isPrime(cur)) primes[++i] = cur;
+		cur += 2;
+	}
+}
+
+int main() {
+  ios::sync_with_stdio(false); cin.tie(NULL);
+
+  map<int, int> mm;
+
+  cin >> M >> N;
+  fill_up_primes();
+
+  for(i=0;i<M;++i) {
+	  set<int> numbers;
+	  map<int, int> m;
+	  for(j=0; j<N; ++j) {
+		int t;
+		cin >> t;
+		planets[i].push_back(t);
+		numbers.insert(t);
+	  }
+
+	  vector<int> unique(numbers.begin(), numbers.end());
+	  sort(unique.begin(), unique.end());
+
+	  for(j=0; j<unique.size(); ++j){
+		  m[unique[j]] = j;
+	  }
+
+	  for(j=0; j<N; ++j) {
+		 planets[i][j] = m[planets[i][j]];
+	  }
+  }
+
+  sort(planets, planets+M, compare);
+
+  int ans=0;
+
+  int t=1;
+  for(i=0;i<M-1;++i){
+	  if(isEqual(planets[i], planets[i+1])){
+		t++;
+	  }else{
+		  ans += t * (t-1) / 2;
+		  t=1;
+	  }
+  }
+  ans += t * (t-1) / 2;
+  cout<<ans<<"\n";
+
+  return 0;
+}