WA on Chef and Digits

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C++

algorithm

I need help with my code for CodeChef's Chef and Digits http://www.codechef.com/APRIL14/problems/ADIGIT/[^]

My code somehow gives WA, I tried every test case that came to my mind and don't know what is wrong. Can someone see the problem?

Algorithm is:

1. Sort a copy of the list of indices x given in the input in M vector.
2. Sweep through the string, counting the occurrences of each digit as I go along. Each time I hit one of the x, I compute the answer from the current counts and put the answer in a array indexed by x.
3.Output the answers in correct order by looping through the original list and looking up the value in answers massive.
Here is my code:

#ifdef _MSC_VER
#define _CRT_SECURE_NO_WARNINGS
#endif
#include<iostream>
#include<vector>
#include<fstream>
#include<algorithm>
#include<string>
#include<cmath>
#include<sstream>
using namespace std;
int n, m, t;
string temp;
int counter[10];
int answers[100002];

int answer(int mas[], int x) {
    int B = 0;
    for (int i = 0; i <= 9; i++)
        B += mas[i] * abs(x - i);
    return B;
}



int main() {
    cin>>n>>m;
    vector<int>M;
    vector<int>M2;
    cin >> temp;
    int B = 0;
    for (int i = 0; i < m; i++) {
        cin>>t;
        M.push_back(t);
        M2.push_back(t);
    }
    sort(M.begin(), M.end());

    int k = 0;

    for (int i = 1; i <= n; i++)
    {
        if (k == M.size()) break;
        if (i == M[k])
        {
            answers[M[k]] = answer(counter, temp[M[k]-1]-'0');
            k++;
        }
        counter[temp[i - 1] - '0']++;
    }

    for (int i = 0; i < m; i++)
        printf("%d\n", answers[M2[i]]);

    return 0;
}