POJ3349【手写Hash】

基础题。
利用邻接表，价值hash值为数组head[]的下标，然后在该链下寻找。

//#include <bits/stdc++.h>#include<iostream>#include<cstdio>#include<cstring>#include<string.h>#include<queue>#include<cmath>#include<algorithm>using namespace std;typedef pair<int,int>PII;typedef long long LL;const int N = 1e5 + 10;const int mod = 1e5 + 7;struct asd{    int x[6];    int nex;}node[N];int head[N], Size;bool flag;void init(){    memset(head, -1, sizeof(head));    Size = 0;}int GetHashV(int num[]){    int sum = 0;    for(int i=0;i<6;i++) sum += sum + num[i];    return sum%mod;}bool Compare(int a[], int b[]){    for(int i=0;i<6;i++) if(a[i] != b[i]) return false;    return true;}void Add(int num[]){    LL pos = GetHashV(num);    for(int i = head[pos];~i;i=node[i].nex){        if(Compare(node[i].x, num))        {            flag = true;            return;        }    }    for(int i=0;i<6;i++) node[Size].x[i] = num[i];    node[Size].nex = head[pos];    head[pos] = Size++;}int main(){    int n, val[6];    init();    scanf("%d",&n);    flag = false;    while(n--){        for(int i=0;i<6;i++) scanf("%d",&val[i]);        if(flag) continue;        sort(val,val+6);        Add(val);    }    if(flag)printf("Twin snowflakes found.\n");    else printf("No two snowflakes are alike.\n");    return 0;}