HDU 4648

#include<iostream>
#include<cstring>
#include<algorithm>
typedef long long ll;
using namespace std;
const int maxn = 100000 + 7;
int Num[maxn];
int HASH[maxn];
int main()
{
    Num[0] = 0;
    int N, M;
    while(scanf("%d %d",&N,&M) != EOF)
    {
        int Max = 0;
        memset(HASH,-1,sizeof(HASH));
        for(int i = 1; i <= N; ++i) scanf("%d",&Num[i]);
        HASH[0] = 0;
        for(int i = 1; i <= N; ++i)
        {
            Num[i] += Num[i-1];
            Num[i] %= M;
            if(Num[i] < 0) Num[i] = (Num[i] + M) % M;
            if(HASH[Num[i]] != -1)
            {
                Max = max(Max, i - HASH[Num[i]]);
            }
            else
            {
                HASH[Num[i]] = i;
            }
        }
        //if(Num[N] == 0) Max = N;
        printf("%d\n",Max);
    }
    return 0;
}