POJ-2593

 1 #include<cstdio>
 2 
 3 #define MAXN 100010
 4 
 5 #define maxx(x,y) ((x)>(y))?(x):(y)
 6 
 7 int a[MAXN];
 8 int b1[MAXN], b2[MAXN];
 9 int c1[MAXN], c2[MAXN];
10 
11 int main(void)
12 {
13   int N, S;
14   scanf("%d", &N);
15   while(N > 0){
16     for(int i = 0; i < N; ++i) scanf("%d", &a[i]);
17     b1[0] = a[0];
18     c1[0] = a[0];
19     for(int i = 1; i < N; ++i){
20       b1[i] = (b1[i-1] > 0) ? (b1[i-1] + a[i]) : a[i];
21       c1[i] = maxx(c1[i-1], b1[i]);
22     }
23     b2[N-1] = a[N-1];
24     c2[N-1] = a[N-1];
25     for(int i = N-2; i >= 0; --i){
26       b2[i] = (b2[i+1] > 0) ? (b2[i+1] + a[i]) : a[i];
27       c2[i] = maxx(c2[i+1], b2[i]);
28     }
29     S = c1[0] + c2[1];
30     for(int i = 2; i < N; ++i)
31       S = maxx(S, (c1[i-1] + c2[i]));
32     printf("%d\n", S);
33     scanf("%d", &N);
34   }
35   return 0;
36 }