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krahets
2023-04-14 04:01:38 +08:00
parent cf431646e9
commit 4d318e8e6b
26 changed files with 469 additions and 295 deletions
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chapter_computational_complexity/space_time_tradeoff.md
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@@ -49,13 +49,13 @@ comments: true
```cpp title="leetcode_two_sum.cpp"
/* 方法一：暴力枚举 */
vector<int> twoSumBruteForce(vector<int>& nums, int target) {
vector<int> twoSumBruteForce(vector<int> &nums, int target) {
int size = nums.size();
// 两层循环，时间复杂度 O(n^2)
for (int i = 0; i < size - 1; i++) {
for (int j = i + 1; j < size; j++) {
if (nums[i] + nums[j] == target)
return { i, j };
return {i, j};
}
}
return {};
@@ -224,14 +224,14 @@ comments: true
```cpp title="leetcode_two_sum.cpp"
/* 方法二：辅助哈希表 */
vector<int> twoSumHashTable(vector<int>& nums, int target) {
vector<int> twoSumHashTable(vector<int> &nums, int target) {
int size = nums.size();
// 辅助哈希表，空间复杂度 O(n)
unordered_map<int, int> dic;
// 单层循环，时间复杂度 O(n)
for (int i = 0; i < size; i++) {
if (dic.find(target - nums[i]) != dic.end()) {
return { dic[target - nums[i]], i };
return {dic[target - nums[i]], i};
}
dic.emplace(nums[i], i);
}