Language: C++

#include <iostream>

#include <cmath>
#include <algorithm>

using namespace std;


#define M 1046527
#define NIL (-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 i,n,h;
    char str[L],com[9];

    for(i = 0; i < M; i++) {
        H[i][0] = '\0';
    }

    scanf("%d",&n);
    for(i = 0; i < n; i++) {
        scanf("%s %s",com,str);
        if(com[0] == 'i') {
            insert(str);
        } else {
            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:31:19: error: 'strlen' was not declared in this scope
   31 |     for(i = 0; i< strlen(str);i++) {
      |                   ^~~~~~
a.cc:5:1: note: 'strlen' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
    4 | #include <algorithm>
  +++ |+#include <cstring>
    5 | 
a.cc: In function 'int find(char*)':
a.cc:52:12: error: 'strcmp' was not declared in this scope
   52 |         if(strcmp(H[h],str) == 0) {
      |            ^~~~~~
a.cc:52:12: note: 'strcmp' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
a.cc:54:19: error: 'strlen' was not declared in this scope
   54 |         } else if(strlen(H[h]) == 0) {
      |                   ^~~~~~
a.cc:54:19: note: 'strlen' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
a.cc: In function 'int insert(char*)':
a.cc:71:12: error: 'strcmp' was not declared in this scope
   71 |         if(strcmp(H[h],str) == 0) {
      |            ^~~~~~
a.cc:71:12: note: 'strcmp' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
a.cc:73:19: error: 'strlen' was not declared in this scope
   73 |         } else if(strlen(H[h]) == 0) {
      |                   ^~~~~~
a.cc:73:19: note: 'strlen' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'
a.cc:74:13: error: 'strcpy' was not declared in this scope
   74 |             strcpy(H[h],str);
      |             ^~~~~~
a.cc:74:13: note: 'strcpy' is defined in header '<cstring>'; this is probably fixable by adding '#include <cstring>'