PAT 2018 春

A 1140 Look-and-say Sequence

　　简单模拟。可能要注意字符串第一个字符和最后一个字符的处理。

 #include <cstdio>
 #include <iostream>
 #include <algorithm>
 #include <string>
 #include <vector>

 using namespace std;
 string numToString(int n)
 {
     string tmpStr;
     int tmpNum;
     while(n > )
     {
         tmpNum = n%;
         n /= ;
         tmpStr = (char)(tmpNum + '')+tmpStr;
     }
     return tmpStr;
 }
 int main()
 {
     int m, tmpNum;;
     string tmpStr, rstStr;
     char tmpC;
     cin >> tmpStr >> m;
     rstStr = tmpStr;
     m--;
     while(m--)
     {
         rstStr.clear();
         tmpNum = ;
         tmpC = 'A';
         for(int i = ; i < tmpStr.size(); ++i)
         {
             if(tmpStr[i] != tmpC)
             {
                 if(i > )
                     rstStr = rstStr + tmpC + numToString(tmpNum);
                 tmpNum = ;
                 tmpC = tmpStr[i];
             }
             else
                 tmpNum++;
             if(i == tmpStr.size()-)
                 rstStr = rstStr + tmpC + numToString(tmpNum);
         }
         tmpStr = rstStr;
     }
     cout << rstStr;
     return ;
 }

A 1141 PAT Ranking of Institutions

　　排序题目。成绩为了尽量无误差，先按A，B，T存储，最后计算并排序。

 #include <cstdio>
 #include <iostream>
 #include <algorithm>
 #include <string>
 #include <unordered_map>
 #include <vector>

 using namespace std;
 typedef struct SCHOOLINFO
 {
     int score;
     int peopleCnt;
     int AScore, BScore, TScore;
     string id;
     SCHOOLINFO():AScore(),BScore(),TScore(),peopleCnt(){}
     SCHOOLINFO(string str):AScore(),BScore(),TScore(),peopleCnt(),id(str){}
 }schoolinfo;
 unordered_map<string, int> schoolFlagMap;
 vector<schoolinfo> schoolDataVec;
 bool cmp(schoolinfo a, schoolinfo b)
 {
     if(a.score != b.score)
         return a.score > b.score;
     else if(a.peopleCnt != b.peopleCnt)
         return a.peopleCnt < b.peopleCnt;
     else
         return a.id < b.id;
 }
 void strToLower(string &tmpStr)
 {
     for(int i = ; i < tmpStr.size(); ++ i)
     {
         if(tmpStr[i] <= 'Z' && tmpStr[i] >= 'A')
             tmpStr[i] = tmpStr[i]-'A'+'a';
     }
 }
 int main()
 {
     int n, index = , tmpNum;
     string tmpId, tmpSchool;
     int tmpScore;
     cin >> n;
     while(n--)
     {
         cin >> tmpId >> tmpScore >> tmpSchool;
         strToLower(tmpSchool);
         if(schoolFlagMap[tmpSchool] == )
         {
             schoolFlagMap[tmpSchool] = index++;
             schoolDataVec.push_back(SCHOOLINFO(tmpSchool));
         }
         tmpNum = schoolFlagMap[tmpSchool]-;
         schoolDataVec[tmpNum].peopleCnt++;
         if(tmpId[] == 'T')
             schoolDataVec[tmpNum].TScore += tmpScore;
         else if(tmpId[] == 'A')
             schoolDataVec[tmpNum].AScore += tmpScore;
         else
             schoolDataVec[tmpNum].BScore += tmpScore;
     }
     for(auto it = schoolDataVec.begin(); it != schoolDataVec.end(); ++it)
         it->score = it->AScore + it->BScore/1.5 + it->TScore*1.5;
     sort(schoolDataVec.begin(), schoolDataVec.end(), cmp);
     int tmpTWS = -, rankCnt = ;
     cout << schoolDataVec.size() << endl;
     for(int i = ; i < schoolDataVec.size(); ++i)
     {
         schoolinfo tmpSchool = schoolDataVec[i];
         if(tmpSchool.score != tmpTWS)
             rankCnt = i+;
         cout << rankCnt << " " << tmpSchool.id << " " <<tmpSchool.score << " " <<tmpSchool.peopleCnt << endl;
         tmpTWS = schoolDataVec[i].score;
     }
     return ;
 }

A 1142 Maximal Clique

　　读懂题目就行，写一个判断是否与所给的其它各点连通的函数。

 #include <cstdio>
 #include <iostream>
 #include <algorithm>
 #include <string>
 #include <unordered_map>
 #include <vector>

 using namespace std;
 #define MAX_SIZE 210
 int route[MAX_SIZE][MAX_SIZE]={};
 int Nv, Ne, M;
 vector<int> cliqueVec;
 bool judge(int u)
 {
     for(auto it = cliqueVec.begin(); it != cliqueVec.end(); ++it)
     {
         if(*it == u)
             continue;
         if(route[*it][u] == )
             return false;
     }
     return true;
 }
 int main()
 {
     cin >> Nv >> Ne;
     int tmpSt, tmpEnd, tmpCnt, tmpNum;
     for(int i = ; i <= Ne; ++i)
     {
         cin >> tmpSt >> tmpEnd;
         route[tmpSt][tmpEnd] = ;
         route[tmpEnd][tmpSt] = ;
     }
     cin >> M;
     while(M--)
     {
         cin >> tmpCnt;
         bool dealFlag = false;
         vector<int> visitFlag(Nv+, );
         cliqueVec.resize(tmpCnt,);
         for(int i = ; i < tmpCnt; ++i)
         {
             cin >> cliqueVec[i];
             visitFlag[cliqueVec[i]] = ;
         }
         for(auto it = cliqueVec.begin(); it != cliqueVec.end(); ++it)
             if(!judge(*it))
                 dealFlag = true;
         if(dealFlag)
         {
             cout << "Not a Clique" << endl;
             continue;
         }
         for(int i = ; i <= Nv; ++i)
             if(visitFlag[i] ==  && judge(i))
                 dealFlag = true;
         if(dealFlag)
         {
             cout << "Not Maximal" <<endl;
             continue;
         }
         cout << "Yes" << endl;
     }
     return ;
 }

A 1143 Lowest Common Ancestor

　　这道题目，深刻理解树的前序遍历和BST的话，是道比较水的题目。

 #include <cstdio>
 #include <iostream>
 #include <algorithm>
 #include <string>
 #include <unordered_map>
 #include <vector>

 using namespace std;
 vector<int> treeKeyVec();
 unordered_map<int, int> keyValMap;
 int M, N;
 void findLCA(int a, int b)
 {
     for(int i = ; i <N; ++i)
     {
         int tmpNum = treeKeyVec[i];
         bool flag = false;
         if(tmpNum == a)
             printf("%d is an ancestor of %d.\n", a, b);
         else if(tmpNum == b)
             printf("%d is an ancestor of %d.\n", b, a);
         else if(tmpNum < max(a,b) && tmpNum > min(a,b))
             printf("LCA of %d and %d is %d.\n", a, b, tmpNum);
         else
             flag = true;
         if(!flag)
             return;
     }
 }
 int main()
 {
     cin >> M >> N;
     int tmpNum;
     for(int i = ; i < N; ++i)
     {
         cin >> tmpNum;
         keyValMap[tmpNum] = ;
         treeKeyVec[i] = tmpNum;
     }
     int tmpNum1, tmpNum2;
     for(int i = ; i < M; ++i)
     {
         cin >> tmpNum1 >> tmpNum2;
         bool flag1 = true, flag2 = true;
         if(keyValMap[tmpNum1] == )
             flag1 = false;
         if(keyValMap[tmpNum2] == )
             flag2 = false;
         if(!flag1 && !flag2)
             printf("ERROR: %d and %d are not found.\n", tmpNum1, tmpNum2);
         else if(!flag1)
             printf("ERROR: %d is not found.\n", tmpNum1);
         else if(!flag2)
             printf("ERROR: %d is not found.\n", tmpNum2);
         else
             findLCA(tmpNum1, tmpNum2);
     }
     return ;
 }