454. 四数相加 II c

typedef struct node{
    int sum;
    int count;
    struct node* repeatnext;
}hash;

void init_hash(hash* h){
    for(int i=0;i<128;i++){
        h[i].sum=0;
        h[i].count=0;
        h[i].repeatnext=NULL;
    }
}

hash* find_hash(hash* h,int number){
    int index=abs(number)%127;
    hash* temp=&h[index];
    while(temp){
        if(temp->sum==number) return temp;
        temp=temp->repeatnext;
    }
    return NULL;
}

void insert_hash(hash* h,int number){
    int index=abs(number)%127;
    if(h[index].count==0){
        h[index].sum=number;
        h[index].count=1;
    }else{
        if(find_hash(h,number)){
            find_hash(h,number)->count++;
        }else{
            hash* temp=(hash*)malloc(sizeof(hash));
            temp->sum=number;
            temp->count=1;
            temp->repeatnext=NULL;
            temp->repeatnext=h[index].repeatnext;
            h[index].repeatnext=temp;
        }
    }
}

int fourSumCount(int* nums1, int nums1Size, int* nums2, int nums2Size, int* nums3, int nums3Size, int* nums4, int nums4Size){
    hash h[128];
    init_hash(h);
    int n=nums1Size;
    int sumcount=0;
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            insert_hash(h,nums1[i]+nums2[j]);
        }
    }
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            int temp=nums3[i]+nums4[j];
            if(find_hash(h,0-temp)){
                sumcount+=find_hash(h,0-temp)->count;
            }
        }
    }
    return sumcount;
}

结果：