Problem Solving►UVa

UVa 10220 - I Love Big Numbers!

Contents

  1. 1. Problem
  2. 2. Solution
  3. 3. Code

Problem

中文網址

Solution

由下往上做每個階乘。
在算每個大數時，邊記下總位數，方便處理進位。

Code

UVa 10220
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#include<cstdio>

int main()
{
    static int factorial[1001][5000] = { { 0 }, { 1 } };
    int i, j, idx = 0, ans[1001] = { 0, 1 };

    for (i = 2; i < 1001; i++)
    {
        for (j = 0; j <= idx; j++)
            factorial[i][j] = factorial[i - 1][j] * i;

        for (j = 0; j <= idx; j++)
        {
            if (factorial[i][j] >= 10)
            {
                int temp = factorial[i][j] / 10;
                factorial[i][j] %= 10;
                factorial[i][j + 1] += temp;

                if (j == idx)//記目前總位數
                    idx++;
            }

            ans[i] += factorial[i][j];
        }
    }

    int n;
    while (scanf("%d", &n) != EOF)
        printf("%d\n", ans[n]);

    return 0;
}