// Sample grader for contestants' use.
//
// Usage: place your input data in the file password.in in the format
//
// line 1: N S
// line 2: hidden_password
//
// Then compile this grader together with your implementation.
// Run the binary to see your guessing strategy at work!
// Set DEBUG to 1 to print all queries.
#include <bits/stdc++.h>
#include <iostream>
#include <sstream>
#include <string>
#include <stdlib.h>
#include <assert.h>
using namespace std;
#define DEBUG 0
#define MAX_QUERIES 50000
#define MAX_N 5000
#define MAX_SIGMA 26
static string password;
static int n, s, numQueries;
static stringstream msg;
static void end(int success) {
cout << (success ? "SUCCESS! " : "ERROR: ") << msg.str() << endl;
exit(0);
}
int query(string q) {
if (++numQueries > MAX_QUERIES) {
msg << "Could not guess the password with " << MAX_QUERIES << " questions.";
end(0);
}
int len = q.size();
// validation
if (len < 1 || len > n) {
msg << "Query '" << q << "' should have length between 1 and "
<< n << " characters.";
end(0);
}
for (int i = 0; i < len; i++) {
if (q[i] < 'a' || q[i] >= 'a' + s) {
msg << "Illegal character '" << q[i] << "' found.";
end(0);
}
}
// while possible, advance one character in q and find its next
// occurrence in password
int i = 0, j = 0, plen = password.size();
while (i < plen && j < len) {
while ((i < plen) && (password[i] != q[j])) {
i++;
}
if (i < plen) { /* found a match */
i++;
j++;
}
}
if (DEBUG) {
cout << "Question #" << numQueries << " [" << q << "] answer " << j << endl;
}
return j;
}
string a[1000];
vector<int> acc(26 , 0);
string merg(string aa , string bb)
{
int s1 = aa.size();
int s2 = bb.size();
string ret = aa;
int j = s2-1;
for(int i = s1;i>=0&&j>=0;i--)
{
string tmp ;
bool ok = 1;
while(ok && j>=0)
{
tmp = ret.substr(0 , i) + bb[j];
tmp+=ret.substr( i , s1 - i );
if(query(tmp)==tmp.size())
{
ret = tmp;
s1++;
j--;
}else ok = 0;
}
}
return ret ;
}
string build(int l, int r )
{
if(l==r)
{
return string( acc[l] , char(l + 'a'));
}
else
{
int mid = (l + r) /2;
string s1 = build(l , mid );
string s2 = build(mid+1 , r);
string ret = merg(s1 , s2);
return ret;
}
}
string guess(int n, int s)
{
int sum = 0;
for(int i = 'a';i<'a' + s -1 ;i++)
{
acc[i-'a'] = query(string(n , char(i)));
sum+=acc[i-'a'];
}
acc[s - 1] = n - sum;
return build(0 , s-1);
}
int main() {
ifstream f("password.in");
f >> n >> s >> password;
f.close();
assert(n && s && !password.empty());
string answer = guess(n, s);
if (DEBUG) {
cout << "Your answer: [" << answer << "]\n";
}
if (answer.compare(password)) {
msg << "Your answer was [" << answer
<< "] which does not match the password [" << password << "].";
end(0);
} else {
msg << "You guessed the password with " << numQueries << " queries.";
end(1);
}
return 0;
}
Compilation message
password.cpp: In function 'std::__cxx11::string merg(std::__cxx11::string, std::__cxx11::string)':
password.cpp:95:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if(query(tmp)==tmp.size())
~~~~~~~~~~^~~~~~~~~~~~
/tmp/ccnvEb0y.o: In function `query(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)':
grader.cpp:(.text+0x0): multiple definition of `query(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >)'
/tmp/ccKDtHY4.o:password.cpp:(.text+0x200): first defined here
/tmp/ccnvEb0y.o: In function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'
/tmp/ccKDtHY4.o:password.cpp:(.text.startup+0x0): first defined here
collect2: error: ld returned 1 exit status
