View Compilation Error

0_0_30473258_28712.cpp:12:1: error: expected initializer before 'int'
 int cnt;
 ^
0_0_30473258_28712.cpp: In function 'bool chk(long long int)':
0_0_30473258_28712.cpp:46:11: error: 'cnt' was not declared in this scope
  build(1, cnt, 1);
           ^
0_0_30473258_28712.cpp:50:25: error: 'b' was not declared in this scope
   int pos = lower_bound(b + 1, b + 1 + cnt, b[sum[i]]-mid)-b; // sum[j] 的位置 pos - cnt
                         ^
0_0_30473258_28712.cpp: In function 'int main()':
0_0_30473258_28712.cpp:65:52: error: 'b' was not declared in this scope
    scanf("%d", a + i), sum[i] = sum[i - 1] + a[i], b[i] = sum[i];
                                                    ^
0_0_30473258_28712.cpp:66:8: error: 'b' was not declared in this scope
   sort(b + 1, b + 1 + n);
        ^
0_0_30473258_28712.cpp:67:3: error: 'cnt' was not declared in this scope
   cnt = unique(b + 1, b + 1 + n) - b - 1;
   ^