搞定了: int alternatingSubarray(int* nums, int numsSize){ int maxlength = -1,currentlength = 1; int i = 1,t = 1,flag = 0; for(i = 1;i maxlength) maxlength = currentlength; } if(maxlength == 1 && flag != 1) return -1; return maxlength; } for循环里面的第一个if判断加一个 t = 1就行了。