POJ 1840 Eqs

来源：互联网发布：中山知乎编辑：程序博客网时间：2024/05/16 13:42

对a1x1^3+a2x2^3+a3x3^3的结果哈希, 然后暴力枚举x4, x5, 在哈希表中二分查找即可

/*author: birdstorm*/#include <vector>#include <list>#include <map>#include <set>#include <deque>#include <queue>#include <stack>#include <bitset>#include <algorithm>#include <functional>#include <numeric>#include <utility>#include <sstream>#include <iostream>#include <iomanip>#include <cstdio>#include <cmath>#include <cstdlib>#include <cctype>#include <string>#include <cstring>#include <cstdio>#include <cmath>#include <cstdlib>#include <ctime>#define MAXN 1005#define N 205#define INF 1<<30#define eps 1.0e-10#define For(i,m,n) for(i=(m);i<n;i++)using namespace std;vector<int> hash;int main(){    int i, j, k, sum, ans=0, cnt=0;    int a, b, c, d, e;    scanf("%d%d%d%d%d",&a,&b,&c,&d,&e);    For(i,-50,51){        if(i==0) continue;        For(j,-50,51){            if(j==0) continue;            For(k,-50,51){                if(k==0) continue;                sum=i*i*i*a+j*j*j*b+k*k*k*c;                hash.push_back(sum);            }        }    }    sort(hash.begin(),hash.end());    For(i,-50,51){        if(i==0) continue;        For(j,-50,51){            if(j==0) continue;            sum=-i*i*i*d-j*j*j*e;            if(binary_search(hash.begin(),hash.end(),sum)) ans+=upper_bound(hash.begin(),hash.end(),sum)-lower_bound(hash.begin(),hash.end(),sum);        }    }    printf("%d\n",ans);    return 0;}

0 0