一道大数题，当做个用数组存大数的模板了

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;
const int Max = 7500;
int ans[Max][750],len[Max];

void init()
{
    int i,j;
    memset(ans,0,sizeof(ans));
    memset(len,0,sizeof(len));
    ans[1][0] = 1,len[1] = 1;
    ans[2][0] = 1,len[2] = 1;
    ans[3][0] = 1,len[3] = 1;
    ans[4][0] = 1,len[4] = 1;
    int t;
    for( i = 5; i < Max; i ++ )
    {
        len[i] = len[i−1];
        for( j = 0; j < len[i−1]; j ++ )
        {
            t = ans[i−1][j] + ans[i−2][j] + ans[i−3][j] + ans[i−4][j];
            ans[i][j] += t % 10000;
            t /= 10000;
            if(t)
            {
                ans[i][j+1] += t;
                len[i] = max(len[i],j+2);
            }
        }
    }
}


int main()
{
    int n,i;
    init();
    while(~scanf("%d",&n))
    {
        i=len[n]−1;  
        printf("%d",ans[n][i−−]);  
        for(;i>=0;i−−)  
            printf("%04d",ans[n][i]);  
        printf("\n");  
    }
    return 0;
}