func_code_string: #include <bits/stdc++.h>   using namespace std;   const double PI = acos(-1);   inline bool EQ(double a, double b) { return fabs(a - b) < 1e-9; }   long long add(long long a, long long b) {     long long ret = a + b;     if (ret >= 1000000007) ret -= 1000000007;     return ret;   }   long long subtract(long long a, long long b) {     long long ret = a - b;     if (ret < 0) ret += 1000000007;     return ret;   }   long long mult(long long a, long long b) {     long long ret = a * b;     if (ret >= 1000000007) ret %= 1000000007;     return ret;   }   long long bigmod(long long a, long long b) {     long long ret = 1;     while (b) {       if (b & 1) ret = mult(ret, a);       b >>= 1;       a = mult(a, a);     }     return ret;   }   long long inverse(long long n) { return bigmod(n, 1000000007 - 2); }   bool base[1000010];   vector<int> primes;   void sieve(int mx) {     mx += 10;     int x = sqrt(mx);     for (int i = 3; i <= x; i += 2)       if (base[i] == 0)         for (int j = i * i, k = i << 1; j < mx; j += k) base[j] = 1;     primes.push_back(2);     for (int i = 3; i < mx; i += 2)       if (base[i] == 0) primes.push_back(i);   }   bool checkBit(int n, int i) { return (n & (1 << i)); }   int setBit(int n, int i) { return (n | (1 << i)); }   int resetBit(int n, int i) { return (n & (~(1 << i))); }   char a[22], b[22];   int c[22];   struct node {     int end;     node *next[2];     node() {       end = 0;       next[0] = next[1] = NULL;     }   } * root;   void insert(int val) {     node *curr = root;     for (int i = 0; i < 18; ++i) {       int id = c[i];       if (curr->next[id] == NULL) curr->next[id] = new node;       curr = curr->next[id];     }     curr->end += val;   }   int query() {     node *curr = root;     for (int i = 0; i < 18; ++i) {       int id = c[i];       if (curr->next[id] == NULL) return 0;       curr = curr->next[id];     }     return curr->end;   }   int main() {     int q;     scanf( %d , &q);     root = new node;     while (q--) {       scanf( %s , a);       scanf( %s , b);       int n = strlen(b);       for (int i = 0; i < 18 - n; ++i) c[i] = 0;       for (int i = 0; i < n; ++i) c[18 - n + i] = ((b[i] -  0 ) & 1);       if (a[0] ==  + )         insert(1);       else if (a[0] ==  - )         insert(-1);       else {         printf( %d n , query());       }     }     return 0;   }   