Language: C++

#include <iostream>
#include <algorithm>
#include <stack>
#include <string>
#include <queue>
#include <cstdlib>
#include <cstdio>
#include <vector>
#include <list>
using namespace std;

#define M 1046527
#define MIL (-1)
#define L 14

char H[M][L];

int getChar(char ch) {
	if( ch == 'A' ) return 1;
	else if ( ch == 'C' ) return 2;
	else if ( ch == 'G' ) return 3;
	else if ( ch == 'T' ) return 4;
	else return 0;
}

long long getKey(char str[]) {
	long long sum = 0, p=1, i;
	for( i = 0; i < strlen(str); i++) {
		sum += p*(getChar(str[i]));
		p *= 5;
	}
	return sum;
}

int h1(int key) {return key % M; }
int h2(int key) {return 1 + (key % (M-1));}

int find(char str[]) {
	long long key, i, h;
	key = getKey(str);
	for( i = 0;; i++) {
		h = (h1(key) + i*h2(key)) % M;
		if( strcmp(H[h], str) == 0 ) return 1;
		else if( strlen(H[h]) == 0 ) return 0;
	}
	return 0;
}

int insert(char str[]) {
	long long key, i, h;
	key = getKey(str);
	for( i = 0;; i++) {
		h = (h1(key) + i*h2(key)) % M;
		if(strcmp(H[h], str) == 0) return 1;
		else if( strlen(H[h]) == 0) {
			strcpy(H[h], str);
			return 0;
		}
	}
	return 0;
}

int main() {
	int n;
	char com[6], str[4];
	cin >> n;
	for(int i = 0; i < M; i++) H[i][0] == '\0';
	for(int i = 0; i < n; i++) {
		scanf("%s %s", com, str);
		if( com[0] == 'i' ) {
			insert(str);
		} else if( com[0] == 'f' ) {
			if( find(str) ) {
				printf("yes\n");
			} else printf("no\n");
		}
	}
	return 0;
}

Compiler output:
a.cc: In function 'long long int getKey(char*)':
a.cc:28:25: error: 'strlen' was not declared in this scope
   28 |         for( i = 0; i < strlen(str); i++) {
      |                         ^~~~~~
a.cc:10:1: note: 'strlen' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
    9 | #include <list>
  +++ |+#include <cstring>
   10 | using namespace std;
a.cc: In function 'int find(char*)':
a.cc:43:21: error: 'strcmp' was not declared in this scope
   43 |                 if( strcmp(H[h], str) == 0 ) return 1;
      |                     ^~~~~~
a.cc:43:21: note: 'strcmp' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
a.cc:44:26: error: 'strlen' was not declared in this scope
   44 |                 else if( strlen(H[h]) == 0 ) return 0;
      |                          ^~~~~~
a.cc:44:26: note: 'strlen' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
a.cc: In function 'int insert(char*)':
a.cc:54:20: error: 'strcmp' was not declared in this scope
   54 |                 if(strcmp(H[h], str) == 0) return 1;
      |                    ^~~~~~
a.cc:54:20: note: 'strcmp' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
a.cc:55:26: error: 'strlen' was not declared in this scope
   55 |                 else if( strlen(H[h]) == 0) {
      |                          ^~~~~~
a.cc:55:26: note: 'strlen' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
a.cc:56:25: error: 'strcpy' was not declared in this scope
   56 |                         strcpy(H[h], str);
      |                         ^~~~~~
a.cc:56:25: note: 'strcpy' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'