HDU 2648——shopping

雜湊函數

#include<vector>#include<iostream>#include<cstring>using namespace std;#define N 5000struct note{char name[35];int price;};note temp;int hash(char *ch)//hash函數，依照我的理解是產生一個離散的數字 {int key=0;int k=131;while(*ch){key=key*k+*ch++;}return key&0x7fffffff;//保證在int範圍內 }int main(){int n,m;int i,j;int key;char name[25];int price;while(cin>>n){vector<note> test[N];for(i=0;i<n;i++){cin>>temp.name;temp.price=0;key=hash(temp.name)%N;//保持在0~N內 test[key].push_back(temp);}cin>>m;char mem[33];strcpy(mem,"memory");int memkey=hash(mem)%N;while(m--){for(i=0;i<n;i++){cin>>price>>name;key=hash(name)%N;for(j=0;j<test[key].size();j++)if(strcmp(name,test[key][j].name)==0){test[key][j].price+=price;break;}}int memprice;for(i=0;i<test[memkey].size();i++)if(strcmp(mem,test[memkey][i].name)==0){memprice=test[memkey][i].price;break;}int sum=1;for(i=0;i<N;i++){for(j=0;j<test[i].size();j++){if(test[i][j].price>memprice)sum++;}}cout<<sum<<endl;}}return 0;}