题解 | #N的阶乘#

#include<stdio.h>
#define MaxSize 3000
void check(int* A, int n) {
    int i, j;
    for (i = 0; i < 8; i++) {
        for (j = n - 1; j > 0; j--) {
            if (A[j] >= 10) {
                A[j - 1] += A[j] / 10;
                A[j] = A[j] % 10;
            }
        }
    }
}
int main() {
    int A[MaxSize] = {0}, i, j, k, n = MaxSize;
    while (scanf("%d", &k) != EOF) {
        for (i = 0; i < n; i++)A[i] = 0;
        A[n - 1] = 1;
        j = 1;
        while (j <= k) {
            for (i = 0; i < n; i++)A[i] *= j;
            j++;
            check(A, n);
        }
        for (i = 0; A[i] == 0; i++);
        while (i < n) {
            printf("%d", A[i]);
            i++;
        }
        printf("\n");
    }
    return 0;
}