uva 11076

计算出每一位上数字i会出现的次数  累加

#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <map>
#include <set>
#include <stack>
#include <vector>
#include <sstream>
#include <string>
#include <cstring>
#include <algorithm>
#include <iostream>
#define maxn 1010
#define INF 0x7fffffff
#define inf 10000000
#define MOD 1000000007
#define ull unsigned long long
#define ll long long
using namespace std;

int a[10], b[10], sum, f[13];
void init()
{
    memset(a, 0, sizeof(a));
    memset(b, 0, sizeof(b));
    sum = 0;
    f[0] = f[1] = 1;
    for(int i = 2; i < 13; ++ i)
        f[i] = f[i-1]*i;
}

int main()
{
    int n, r;
    while(scanf("%d", &n) == 1 && n)
    {
        init();
        for(int i = 0; i < n; ++ i) {scanf("%d", &r); a[r] ++; sum ++;}
        for(int i = 1; i < 10; ++ i)
            if(a[i]){
                b[i] = f[sum-1];
                for(int j = 0; j < 10; ++ j)
                    if(a[j])
                        b[i] /= i == j ? f[a[j]-1]:f[a[j]];
            }
        ll ans = 0;
        for(int i = 0; i < n; ++ i)
        {
            ans *= 10;
            for(int j = 0; j < 10; ++ j)
                ans += j*b[j];
        }
        printf("%lld\n", ans);
    }
    return 0;
}