Codeforces Flipping game 动态规划基础

题目链接：http://codeforces.com/problemset/problem/327/A

这道题目有O(N^3)的做法，这里转化为动态规划求解，复杂度是O(N)

 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
 #include <cmath>
 #include <cctype>
 #include <algorithm>
 #include <queue>
 #include <set>
 #include <queue>
 #include <list>
 #include <map>
 using namespace std;
 #define INF 0x3f3f3f3f
 int a[], b[], c[];
 int main ( void )
 {
     int n, n1=, cnt=;
     while (~scanf("%d", &n))
     {
         n1 = cnt = ;
         memset(a, , sizeof(a));
         memset(b, , sizeof(b));
         for (int i=; i<=n; ++i){
             scanf("%d",a+i); if(a[i]) n1++;
             if (a[i]) b[i]=-; else b[i]=;
         }
         c[] = ;
         for (int i = ; i <= n; ++i)
         {
             c[i] = c[i-] + b[i];
         }
         int Max = -INF, Min = c[];
         for (int i = ; i <= n; ++i) {
             if (c[i] - Min > Max) Max = c[i]-Min;
             if (c[i] < Min) Min = c[i];
         }
         printf("%d\n",n1+Max);
     }
         return ;
 }            

转化为子序列的最大连续和