TCO 2014 Round 1A

顺利搞出  A B 两题，然后压线晋级了，手速场。

A 题 ， 求排列最小的，肯定从后往前来做，维护一个最小的set，只是第一个字母要特判一下。

   1:  #line 5 "EllysSortingTrimmer.cpp"

   2:  #include <vector>

   3:  #include <list>

   4:  #include <map>

   5:  #include <set>

   6:  #include <deque>

   7:  #include <stack>

   8:  #include <bitset>

   9:  #include <algorithm>

  10:  #include <functional>

  11:  #include <numeric>

  12:  #include <utility>

  13:  #include <sstream>

  14:  #include <iostream>

  15:  #include <iomanip>

  16:  #include <cstdio>

  17:  #include <cmath>

  18:  #include <cstdlib>

  19:  #include <ctime>

  20:  #include <cstring>

  21:  using namespace std;

  22:  int i,j,k;

  23:  #define REP(i,n) for((i)=0;(i)<(int)(n);(i)++)

  24:  #define snuke(c,itr) for(__typeof((c).begin()) itr=(c).begin();itr!=(c).end();itr++)

  25:   

  26:   

  27:  class EllysSortingTrimmer

  28:  {

  29:  public:

  30:  string getMin(string S, int L)

  31:  {

  32:      vector<char> s;

  33:      for(int i=1; i<S.size(); i++) s.push_back(S[i]);

  34:      sort(s.begin(),s.end());

  35:      vector<char> t;

  36:      for(int i=0; i<L-1; i++) t.push_back(s[i]);

  37:      t.push_back(S[0]);

  38:      sort(t.begin(), t.end());

  39:      string ret;

  40:      for(int i=0; i<L; i++) ret += t[i];

  41:      return ret;

  42:  }

  43:   

  44:   

  45:  };

  46:   

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B题  不要搞成匹配的问题，每一个字母都有一个位置范围，所以只要维护一个set，保证其能够被写入，其余时间都插入最小就OK

   1:  #line 5 "EllysScrabble.cpp"

   2:  #include <vector>

   3:  #include <list>

   4:  #include <map>

   5:  #include <set>

   6:  #include <deque>

   7:  #include <stack>

   8:  #include <bitset>

   9:  #include <algorithm>

  10:  #include <functional>

  11:  #include <numeric>

  12:  #include <utility>

  13:  #include <sstream>

  14:  #include <iostream>

  15:  #include <iomanip>

  16:  #include <cstdio>

  17:  #include <cmath>

  18:  #include <cstdlib>

  19:  #include <ctime>

  20:  #include <cstring>

  21:  using namespace std;

  22:  int i,j,k;

  23:  #define REP(i,n) for((i)=0;(i)<(int)(n);(i)++)

  24:  #define snuke(c,itr) for(__typeof((c).begin()) itr=(c).begin();itr!=(c).end();itr++)

  25:   

  26:   

  27:  class EllysScrabble

  28:  {

  29:  public:

  30:  string getMin(string letters, int maxDistance)

  31:  {

  32:      pair<char, int> X;

  33:      vector<pair<char, int> > S;

  34:      for(int i=0; i<letters.size(); i++)

  35:      {

  36:          S.push_back( make_pair(letters[i], i));

  37:      }

  38:   

  39:      string ret;

  40:   

  41:      vector<pair<char, int> > tmp;

  42:      for(int i=0; i<  min(letters.size() *1.0,maxDistance + 1.0); i++) tmp.push_back(make_pair(letters[i], i));

  43:      for(int i=0; i<letters.size(); i++)

  44:      {

  45:          // search

  46:          sort(tmp.begin(), tmp.end());

  47:          bool flag = 0;

  48:          for(int j=0; j< tmp.size(); j++)

  49:          {

  50:              if(i - tmp[j].second == maxDistance)

  51:              {

  52:                  ret += tmp[j].first;

  53:                  tmp.erase(tmp.begin() + j);

  54:                  flag = true;

  55:                  break;

  56:              }

  57:          }

  58:          if(flag == false)

  59:          {

  60:              ret += tmp[0].first;

  61:              tmp.erase(tmp.begin());

  62:          }

  63:   

  64:          // push

  65:          if(i + maxDistance + 1 < letters.size())

  66:          {

  67:              tmp.push_back(S[ i+ maxDistance +1]);

  68:          }

  69:      }

  70:      return ret;

  71:  }

  72:   

  73:   

  74:  };

  75:   

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C题   这个题目开始的时候没搞出来，其实当时已经发下了 YYY， NY YN3种情况肯定会有一个是亮的。但是没有仔细想。这个为什么贪心是对的呢？给出每一个序列，NY YN YYY一定是最大的，这个仔细推了一下好像是对的！但是有没有严格证明出来。

#line 5 "EllysLamps.cpp"
#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cstring>
using namespace std;
int i,j,k;
#define REP(i,n) for((i)=0;(i)<(int)(n);(i)++)
#define snuke(c,itr) for(__typeof((c).begin()) itr=(c).begin();itr!=(c).end();itr++)

class EllysLamps
{
public:
int getMin(string lamps)
{
    int num = 0;

    for(int i=0; i<lamps.size();)
    {
        if(i+1 < lamps.size() && lamps[i] != lamps[i+1])
        {
            i+=2;
            num++;
        }else if(i+2 < lamps.size() && lamps[i] == lamps[i+1] && lamps[i] == lamps[i+2] && lamps[i]== 'Y')
        {
            i+=3;
            num++;
        }else i++;
    }
    return num;
}

};

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