hdu 1496(hash)

/*
*  hash+数学，很好的题 
*  对整数求hash，采用除余法，及线性探测解决冲突 
*  注意：devc++中不能定义全局变量count，它和库函数中的函数名同名了 
*/
#include 
#include 
#include 

using namespace std;

const int M = 175447;

int counts[M];
int result[M];
int temp[101];

int hashInt(int s) {
    int k = s % M;
    if (k < 0) k += M;
    while (counts[k] && result[k]!=s) k = (k + 1) % M;
    return k;
}

int solve(int a, int b, int c, int d) {
    if (a>0&&b>0&&c>0&&d>0 || a<0&&b<0&&c<0&&d<0) return 0;
    memset(counts, 0, sizeof(counts));
    int s, p, i, j;
    for (i=1; i<101; ++i) {
        for (j=1; j<101; ++j) {
            s = a * temp[i] + b * temp[j];
            p = hashInt(s);
            result[p] = s;
            ++counts[p];
        }
    }
    int ans = 0;
    for (i=1; i<101; ++i) {
        for (j=1; j<101; ++j) {
            s = -(c * temp[i] + d * temp[j]);
            p = hashInt(s);
            ans += counts[p];
        }
    }
    return ans;
}

int main() {
    int a, b, c, d;
    for (int i=1; i<101; ++i) temp[i] = i * i;
    while (scanf("%d%d%d%d", &a, &b, &c, &d) != EOF) {
        int ans = solve(a, b, c, d);
        printf ("%d\n", ans<<4);
    }
    return 0;
}

 

转载于:https://www.cnblogs.com/try86/archive/2012/04/09/2439535.html