417 - Word Index, uva, solution

simple BFS using a queue.

#include <iostream> 
#include <sstream> 
#include <cstring> 
#include <cstdio> 
#include <cstdlib> 
#include <algorithm> 
#include <ctime> 
#include <cctype> 
#include <cmath> 
#include <vector> 
#include <map> 
#include <set> 
#include <queue>
#include<bitset>
#define foreach(it, l) for (typeof(l.begin()) it = l.begin(); it != l.end(); it++)
#define db(a) \
cout << #a << " = " << a << endl
#define db2(a, b) \
cout << #a << " = " << a << " " << #b << " = " << b << endl
#define inf (1<<30)
using namespace std;
int main() {
 #ifdef dennisbot
  freopen("in.in", "r", stdin);
 #endif
 string s;
 map<string, int> mapa;
 queue<string> q;
 q.push("");
 int cont = 0;
 while (!q.empty()) {
  string val = q.front();
  q.pop();
  mapa[val] = cont++;
  if (val.size() == 5) continue;
  for (char i = (val == "") ? 'a' : val[val.size() - 1] + 1; i < 'z' + 1; i++) {
   q.push(val + i);
  }
 }
 char linea[6];
 while (gets(linea)) { 
  printf("%d\n", mapa[linea]); 
 }
 return 0;
}