623.cpp

#include <bits/stdc++.h>
using namespace std;
char a[1001][10000];
void swap(char b[10000]) {
    int temp, i, j, l;
    l = strlen(b);
    for (i = 0, j = l - 1; i < l / 2; i++, j--) {
        temp = b[i];
        b[i] = b[j];
        b[j] = temp;
    }
}
void work(char a[10000], char b[10000], int n) {
    int i, j, onhand = 0, k, l;
    l = strlen(a);
    for (i = l - 1, j = 0; i >= 0; i--) {
        k = ((a[i] - 48) * n) + onhand;
        b[j] = (k % 10) + 48;
        onhand = k / 10;
        j++;
    }
    while (onhand > 0) {
        b[j] = (onhand % 10) + 48;
        onhand /= 10;
        j++;
    }
    b[j] = '\0';
    swap(b);
}

int main() {
    int i, j, n;
    strcpy(a[0], "1");
    strcpy(a[1], "1");
    for (i = 2; i < 1001; i++) {
        work(a[i - 1], a[i], i);
    }
    while (scanf("%d", &n) == 1) {
        printf("%d!\n%s\n", n, a[n]);
    }
    return 0;
}