廈大oj1438簡單題、map

#include<iostream>  #include <map>  #include <string>  #include <fstream>  using namespace std;  int main(){  map<string, int> tongji;  map<string, int>::iterator it;  int shuru1 = 0;  cin>>shuru1;  ifstream ifs("shuju.txt");//  //ifs>>shuru1;//  string shuru2;  int count = 3 * shuru1;  string rank[3];  while(count--){  cin>>shuru2;  //ifs>>shuru2;//  it = tongji.find(shuru2);  if(it == tongji.end()){  tongji[shuru2] = 1;  //tongji.insert(pair<string, int>(shuru2, 1));  }else{  tongji[shuru2]++;  }  }  int max_num;  string max_str;  for(int i = 0; i < 3; i++){  max_num = 0;  for(it = tongji.begin(); it != tongji.end(); it++){  if(it->second > max_num){  max_str = it->first;  max_num = it->second;  }else if(it->second == max_num){  if(it->first < max_str){  max_str = it->first;  }  }  }  if(i == 2){  rank[2] = max_str;  tongji.erase(max_str);  }else if(i == 0){  rank[0] = max_str;  tongji.erase(max_str);  }else if(i == 1){  rank[1] = max_str;  tongji.erase(max_str);  }  }  if(rank[0] > rank[1]){  string temp;  temp = rank[0];  rank[0] = rank[1];  rank[1] = temp;  }  if(rank[0] > rank[2]){  string temp;  temp = rank[0];  rank[0] = rank[2];  rank[2] = temp;  }  if(rank[1] > rank[2]){  string temp;  temp = rank[1];  rank[1] = rank[2];  rank[2] = temp;  }  cout<<rank[0]<<" "<<rank[1]<<" "<<rank[2];  //system("pause");  return 0;  }