【HDOJ】1171 Big Event in HDU

母函数，先要算搞清楚组合数可能的最大值。非常大。N种设备的最大VAL*最大数量。

#include <stdio.h>
#include <string.h>

#define MAXNUM 500000

typedef struct {
    int val, num;
} fac_st;

fac_st facs[55];
int c1[MAXNUM], c2[MAXNUM];

int main() {
    int n, sum, tmp;
    int i, j, k;

    while (scanf("%d", &n) != EOF && (n>=0)) {
        sum = 0;
        for (i=1; i<=n; ++i) {
            scanf("%d %d", &facs[i].val, &facs[i].num);
            sum += facs[i].val * facs[i].num;
        }
        memset(c1, 0, sizeof(c1));
        memset(c2, 0, sizeof(c2));
        for (i=0, j=0; i<=facs[1].num; ++i, j+=facs[1].val)
            c1[j] = 1;
        for (i=2; i<=n; ++i) {
            for (j=0; j<=sum; ++j) {
                tmp = facs[i].val * facs[i].num;
                for (k=0; k<=tmp && (k+j)<=sum; k+=facs[i].val)
                    c2[k+j] += c1[j];
            }
            for (j=0; j<=sum; ++j) {
                c1[j] = c2[j];
                c2[j] = 0;
            }
        }
        k = sum/2;
        if (c1[k])
            printf("%d %d
", sum-k, k);
        else {
            for (i=k+1; i<=sum; ++i)
                if (c1[i]) {
                    printf("%d %d
", i, sum-i);
                    break;
                }
        }
    }

    return 0;
}