1. two sum
2021. 8. 17. 10:31ㆍPS/leetcode
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class Solution {
public int[] twoSum(int[] nums, int target) {
for (int i = 0; i < nums.length - 1; i++) {
int answer = target - nums[i];
for (int j = i + 1; j < nums.length; j++) {
if (answer - nums[j] == 0) {
return new int[] {i, j};
}
}
}
return null;
}
}
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cs |
1. 그냥 생각하기 쉽게 푼거
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class Solution {
public int[] twoSum(int[] nums, int target) {
HashMap<Integer, Integer> hashMap = new HashMap<>();
for (int i = 0; i < nums.length; i++) {
if (hashMap.containsKey(target - nums[i])) {
return new int[] {i, hashMap.get(target - nums[i])};
} else {
hashMap.put(nums[i], i);
}
}
return null;
}
}
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cs |
2. 다른 방법 찾아본거
HashMap 쓸 생각 못했는데 O(n)이라 훨씬 빠른듯