题目：

  

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解析： 

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代码：    

public int maxSubarraySumCircular(int[] nums) {int sum = 0;int n = nums.length;int[] f = new int[n+1];int[] g = new int[n+1];int ret = 0, fmax = -0x3f3f3f3f, gmin = Integer.MAX_VALUE;for(int i = 1; i <= n; i++){int x = nums[i-1];f[i] = Math.max(x,f[i-1] + x);fmax = Math.max(fmax,f[i]);g[i] = Math.min(x,g[i-1]+ x);gmin = Math.min(gmin,g[i]);sum += x;}return sum == gmin ? fmax : Math.max(fmax,sum-gmin);}