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hello-algo/codes/dart/chapter_searching/two_sum.dart

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/**
* File: two_sum.dart
* Created Time: 2023-2-11
* Author: Jefferson (JeffersonHuang77@gmail.com)
*/
import 'dart:collection';
/* 方法一: 暴力枚举 */
List<int> twoSumBruteForce(List<int> nums, int target) {
int size = nums.length;
for (var i = 0; i < size - 1; i++) {
for (var j = i + 1; j < size; j++) {
if (nums[i] + nums[j] == target) return [i, j];
}
}
return [0];
}
/* 方法二: 辅助哈希表 */
List<int> twoSumHashTable(List<int> nums, int target) {
int size = nums.length;
Map<int, int> dic = HashMap();
for (var i = 0; i < size; i++) {
if (dic.containsKey(target - nums[i])) {
return [dic[target - nums[i]]!, i];
}
dic.putIfAbsent(nums[i], () => i);
}
return [0];
}
/* Driver Code */
int main() {
// ======= Test Case =======
List<int> nums = [2, 7, 11, 15];
int target = 13;
// ====== Driver Code ======
// 方法一
List<int> res = twoSumBruteForce(nums, target);
print('方法一 res = $res');
// 方法二
res = twoSumHashTable(nums, target);
print('方法二 res = $res');
return 0;
}