codeforces 192a

link: http://codeforces.com/contest/330/problem/A

brute force.

 /*
 ID: zypz4571
 LANG: C++
 TASK: 191a.cpp
  */

 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
 #include <cmath>
 #include <cctype>
 #include <algorithm>
 #include <queue>
 #include <set>
 #include <queue>
 #include <list>
 #include <map>
 #define INF 0x3f3f3f3f
 #define mid int m=(l+r)/2
 using namespace std;
 int a[];
 int main ( int argc, char *argv[] )
 {
 #ifndef ONLINE_JUDGE
     freopen("191a.in", "r", stdin);
 #endif
     int n, n1=, cnt=, Max=; scanf("%d", &n);
     for (int i=; i<n; ++i){
         scanf("%d",a+i); if(a[i]) n1++;
     }
     if (n1 == n) Max = n1-;
     else
     {
         Max = n1;
         for (int i=; i<n; ++i) {
             for (int j=; j<n; ++j) {
                 cnt = n1;
                 for (int k=i; k<=j; ++k) {
                     if (!a[k]) cnt++; else cnt--;
                 }
                 if (cnt > Max) Max = cnt;
             }
         }
     }
     printf("%d\n", Max);

         return EXIT_SUCCESS;
 }                /* ----------  end of function main  ---------- */

It is so easy. However, I got a WA at first. sad......