Here my solution. In c[x] I store how much I have elements with key x in set. So it is in this range M ≤ N ≤ 25000. But when I set size of c to 25000 I have got Crash on 4 test. What is wrong in my solution?
#include <stdio.h>
#include <vector>
#include <set>
#include <stdlib.h>
#include <algorithm>


int main(){
    /*freopen("input.txt","r",stdin);
    freopen("output.txt","w",stdout);*/
    int m,b,c[200000],l,r,d;
    std::vector <int> a;
    std::set <int> set;
    std::set <int>::iterator it;
    memset(c,0,sizeof(c));
    scanf("%d",&m);
    scanf("%d",&b);
    while (b!=-1){
        a.push_back(b);
        scanf("%d",&b);
    }
    d=a.size();
    for (int i=0; i<std::min(m,d); i++){
        set.insert(a[i]);
        c[a[i]]++;
    }
    if (m-1<d && m!=0){
        l=0; r=m-1;
        while (r<d-1){
            it=set.end();
            it--;
            printf("%d\n",*it);
            r++;
            c[a[r]]++;
            set.insert(a[r]);
            c[a[l]]--;
            if (c[a[l]]==0) set.erase(a[l]);
            l++;
        }
    }
    if (set.size()>0){
        it=set.end();
        it--;
        printf("%d\n",*it);
    }else{printf("0");}
//    fclose(stdin); fclose(stdout);
}

Edited by author 05.11.2011 03:44

Hello,
as far as I see, you index C with values from A, which can contain numbers from 0 to 100000.

Edited by author 05.11.2011 23:20