Source code for submission s1069

all.cpp

  1. #include <algorithm>
  2. #include <cctype>
  3. #include <cmath>
  4. #include <cstdio>
  5. #include <cstring>
  6. #include <iostream>
  7. #include <list>
  8. #include <map>
  9. #include <queue>
  10. #include <set>
  11. #include <sstream>
  12. #include <stack>
  13. #include <string>
  14. #include <utility>
  15. #include <vector>
  16. using namespace std;
  17.  
  18. #define DEBUG(x) cerr << ">> " << #x << ": " << x << endl;
  19. #define REP(i,a) for (int i =0; i < (a);++i)
  20. #define FOR(i,a,b) for (int i = (a); i <= (b); ++i)
  21.  
  22. int num, edgecount;
  23. int* degrees;
  24.  
  25. int main() {
  26.  
  27.    while (scanf("%d%d", &num, &edgecount) != EOF)
  28.    {
  29.      degrees = new int[num];
  30.      for (int j = 0; j < num; j++)
  31.      {
  32.        degrees[j] = 0;
  33.      }
  34.      for (int i = 0; i < edgecount; i++)
  35.      {
  36.        int from, to;
  37.        scanf("%d%d", &from, &to);
  38.        degrees[from-1]++;
  39.        degrees[to-1]++;
  40.      }
  41.      int deg4 = 0;
  42.      int deg3 = 0;
  43.      int deg2 = 0;
  44.      int deg1 = 0;
  45.      for (int j = 0; j < num; j++)
  46.      {
  47.         switch(degrees[j])
  48. 	{
  49. 	  case 1: deg1++; break;
  50. 	  case 2: deg2++; break;
  51. 	  case 3: deg3++; break;
  52. 	  case 4: deg4++; break;
  53. 	  default: deg4++; break;
  54. 	}
  55.      }
  56.      if (deg4 > 0) { printf("YES\n"); }
  57.      else if (deg3 < 0) { printf("NO\n");  }
  58.      else
  59.      {
  60.        if (deg3 >= 2) { printf("YES\n"); } else { printf("NO\n");  }
  61.      }
  62.  
  63.      delete[] degrees;
  64.    }
  65.  
  66.   return 0;
  67. }