返回错误值的双哈希函数

我正在创建一个双哈希图，但插入后删除功能不起作用。我遵循相同的格式来增加索引，但它只是没有达到正确的索引。

class RHHM {
    unsigned int hash2( int key ) {
        return key % (M-1) + 1;
    }
    //Private variables
    hashNode ** map;        //Backing array
    unsigned int M;   //Capacity of array
    //If index that key hashes to is empty, insert. Else, replace value at hashed index.
    int insert( int key, char value ) {
        int f = hash( key );
        int f2 = hash2 ( key );
        int p = 0;
        int h = f + (p * f2) % M;
        while( map[h] != NULL ) {
            if( p == M )
                return -1 * p;
            if( map[h]->key == key ) {
                map[h]->value = value;
                return p;
            }
            else {
                ++p;
                h = f + (p * f2) % M;
            }
        }
        map[h] = new hashNode( key, value );
        return p;
    }
int remove( int key, char &value) {
        int f = hash( key );
        int f2 = hash2 ( key );
        int p = 0;                         //Keeps track of how many indexes have been checked
        int h = f + (p * f2) % M;
        while( map[h] != NULL ) {
            if( p  == M )              //If item is not found in table, return false
                return -1 * p;
            if( key == map[h]->key )        //If key is found, break out of loop
                break;
            else {
                ++p;
                h = f + (p * f2) % M;  //Wrap around array if necessary
            }
        }
        if( map[h] == NULL )                //If end of cluster reached, return false
            return -1 * p;
        value = map[h]->value;              //Stores the value of the item to be deleted
        delete map[h];                      //Delete the item the user specified
        map[h] = NULL;
        ++p;
        h = f + (p * f2) % M;
        for( ; map[h] != NULL; h = f + (p * f2) % M) {     //While still in the cluster, remove and     reinsert all items
            int tempKey = map[h]->key;
            char tempValue = map[h]->value;
            delete map[h];
            map[h] = NULL;
            insert(tempKey, tempValue);
            ++p;
        }
        return p;
    }
}

这是我的主要内容：

RHHM bh(10);
bh.insert(0, 'A');
bh.insert(10, 'B');
bh.insert(20, 'C');
bh.print(std::cout);

输出：

<[ 0:A, - , 10:B, 20:C, - , - , - , - , - , - ]>

如您所见，第一个索引哈希为 0 。由于10键与0冲突，双哈希（10）应该哈希到1，但它的哈希到2。为什么它返回错误的值？