代码挑战：找到单一数字-C++
【摘要】 Given a non-empty array of integers, every element appears twice except for one. Find that single one.方案一：class SingleNumber {public: int singleNumber(vector<int>& nums) { int result = nu...
Given a non-empty array of integers, every element appears twice except for one. Find that single one.
方案一：
class SingleNumber {
public:
int singleNumber(vector<int>& nums) {
int result = nums[0];
int len = nums.size();
for (int i = 1; i < len; i++) {
result = result ^ nums[i];
}
return result;
}
};
测试案例：
TEST_METHOD(TestMethod1)
{
SingleNumber singleNumber;
int numsArray[] = { 2, 2, 1 };
vector<int> nums;
nums.insert(nums.begin(), std::begin(numsArray), std::end(numsArray));
Assert::AreEqual(1, singleNumber.singleNumber(nums));
}
TEST_METHOD(TestMethod2)
{
SingleNumber singleNumber;
int numsArray[] = { 4,1,2,1,2 };
vector<int> nums;
nums.insert(nums.begin(), std::begin(numsArray), std::end(numsArray));
Assert::AreEqual(4, singleNumber.singleNumber(nums));
}
方案二：
class SingleNumberWay1 {
public:
int singleNumber(vector<int>& nums) {
unordered_set<int> set;
for (int i = 0; i < nums.size(); i++) {
int v = nums[i];
std::unordered_set<int>::const_iterator iter = set.find(v);
if (iter== set.end()) {
set.insert(v);
}
else {
set.erase(iter);
}
}
return *(set.begin());
}
};
测试案例：
TEST_METHOD(TestMethod1)
{
SingleNumberWay1 singleNumber;
int numsArray[] = { 2, 2, 1 };
vector<int> nums;
nums.insert(nums.begin(), std::begin(numsArray), std::end(numsArray));
Assert::AreEqual(1, singleNumber.singleNumber(nums));
}
TEST_METHOD(TestMethod2)
{
SingleNumberWay1 singleNumber;
int numsArray[] = { 4,1,2,1,2 };
vector<int> nums;
nums.insert(nums.begin(), std::begin(numsArray), std::end(numsArray));
Assert::AreEqual(4, singleNumber.singleNumber(nums));
}
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