为啥全WA了啊，感觉没问题啊

Hayaizo @ 2022-10-22 11:34:58

#include<iostream>
#include<string>
using namespace std;
int n, num, a;
int arr[10000000];
int number;
int main(void) {
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> num >> a;
        arr[10000000] = { 0 };
        arr[0] = { 1 };
        for (int i = 1; i <= num; i++) {
            for (int j = 0; j < 100;j++) {
                arr[j] *= i;
            }
            for (int j = 0; j < 100; j++) {
                if (arr[j] > 9) {
                    arr[j + 1] += arr[j] / 10;
                    arr[j] %= 10;
                }
            }
        }
        //删除前导0
        int k = 0;
        for (k = 100; k >= 0 && arr[k] == 0; k--) {
            ;
        }
        int cnt = 0;
        for (int i = 0; i < k; i++) {
            if (arr[i] == a) {
                cnt++;
            }
        }
        cout << cnt<<endl;
    }
    return 0;
}

by twrjx @ 2022-10-22 11:41:43

题号是什么

by OoXiao_QioO @ 2022-10-22 11:43:25

@twrjx P1591

by Hayaizo @ 2022-10-22 11:54:28

#include<iostream>
#include<string>
using namespace std;
int n, num, a;
int arr[10000];
int number;
int main(void) {
    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> num >> a;
        memset(arr, 0,sizeof(arr));
        arr[0] = { 1 };
        for (int i = 1; i <= num; i++) {
            for (int j = 0; j < 100;j++) {
                arr[j] *= i;
            }
            for (int j = 0; j < 100; j++) {
                if (arr[j] > 9) {
                    arr[j + 1] += arr[j] / 10;
                    arr[j] %= 10;
                }
            }
        }
        //删除前导0
        int k = 0;
        for (k = 100; k >= 0 && arr[k] == 0; k--) {
            ;
        }
        int cnt = 0;
        for (int i = 0; i <= k; i++) {
            if (arr[i] == a) {
                cnt++;
            }
        }
        cout << cnt<<endl;
    }
    return 0;
}

改成这样也不行

by Lucas2024 @ 2022-10-24 20:39:36

#include<iostream>
#include<cstring>
using namespace std;
int a[2570],l,ans,t,n,m;
int main(){
    int i,j;
    cin>>t;
    while(t){
        t--;
        cin>>n>>m;
        ans=0;
        memset(a,0,sizeof(a));
        l=1;
        a[0]=1;//初始化为1，不能为0，不然怎么乘都是0 
        for(i=2;i<=n;i++){
            for(j=0;j<l;j++){
                a[j]*=i;
            }
            for(j=0;j<l;j++){
                if(a[j]>9){//进位 
                    a[j+1]+=a[j]/10;
                    a[j]%=10;
                }
            }
            while(a[l]!=0){//l+1若>0，长度++ 
                if(a[l]>9){//再次判断进位 
                    a[l+1]+=a[l]/10;
                    a[l]%=10;
                }
                l++;
            }
        }
        while(l--){//当长度为0时，ans表示数字m的个数 
            if(a[l]==m){
                ans++;
            }
        }
        cout<<ans<<endl;
    }
    return 0;
}
/*
正确的