算法笔记--哈希

问题A：谁是你的潜在朋友

#include<cstdio>
#include<cstring>
int main(){
    const int maxn = 210;
    int N, M;
    int hashTable[maxn] = {0};
    int stu[maxn] = {0};

    while(scanf("%d%d", &N, &M) != EOF){

    memset(hashTable, 0, sizeof(hashTable));

    for(int i=1; i <= N; i++){
        int P;
        do{
        scanf("%d", &P);
        stu[i-1] = P;
        hashTable[P] ++;
        }while(P < 1 || P > M);
    }


    for(int i=1; i <= N; i++){
        int k = stu[i-1];
        if(hashTable[k] >= 2){
            printf("%d
", hashTable[k]-1);
        }else{
            printf("BeiJu
");
        }
    }}

    return 0;
}

注意：codeup是多点测试，所以每一次hash表得初始化为0，否则会一直出错的啊！！！

 因为一行出错的心态崩 /(ㄒoㄒ)/~~，hash表初始化建议：

#include<cstring>
memset(hashTable, 0, sizeof(hashTable));