Wheres my wrong? help pleas
#include <bits/stdc++.h>

const int maxn = (int)1e6;
const int mod = (int)1e9 + 7;

using namespace std;

int n;
int dp[maxn]={-1};

int calc(int n){
    int res=n;
    dp[0]=0;
    if(dp[n] != -1)
        return dp[n];
     for(int i=1; i*i <= n; i++){
         res=min(res,1+calc(n-i*i));
     }
    return dp[n]=res;
}

int main(){
    scanf("%d",&n);
    printf("%d\n", calc(n));

    return 0;
}

Edited by author 20.12.2015 23:27