๐Ÿš€ LeetCode Top 150 โ€” ์ง„ํ–‰ ๋กœ๊ทธ #1

๋ฐœํ–‰: (2026๋…„ 3์›” 1์ผ ์˜คํ›„ 07:06 GMT+9)
3 ๋ถ„ ์†Œ์š”
์›๋ฌธ: Dev.to

Source: Dev.to

Progress

์ €๋Š” ๋ฐ์ดํ„ฐ ๊ตฌ์กฐโ€ฏ&โ€ฏ์•Œ๊ณ ๋ฆฌ์ฆ˜ ๊ธฐ์ดˆ๋ฅผ ๋‹ค์ง€๊ธฐ ์œ„ํ•ด Topโ€ฏ150 LeetCode ์—ฌ์ •์„ ๊ณต์‹์ ์œผ๋กœ ์‹œ์ž‘ํ–ˆ์Šต๋‹ˆ๋‹ค.
Progress: 3โ€ฏ/โ€ฏ150 ๋ฌธ์ œ ํ•ด๊ฒฐ.

๋ฌธ์ œ๋ฅผ ์„œ๋‘๋ฅด๊ธฐ๋ณด๋‹ค ํŒจํ„ด์„ ์ดํ•ดํ•˜๊ณ , ์‚ฌ๊ณ ๋ ฅ์„ ํ–ฅ์ƒ์‹œํ‚ค๋ฉฐ, ์‹œ๊ฐ„์ด ์ง€๋‚จ์— ๋”ฐ๋ผ ๋” ๊น”๋”ํ•œ ํ’€์ด๋ฅผ ์ž‘์„ฑํ•˜๋Š” ๋ฐ ์ง‘์ค‘ํ•˜๊ณ  ์žˆ์Šต๋‹ˆ๋‹ค.

Approach: Merge Sorted Array (Pointerโ€‘based merging)

Key Learning: ์ •๋ ฌ์—๋งŒ ์˜์กดํ•˜์ง€ ๋ง๊ณ  ํฌ์ธํ„ฐ ๊ธฐ๋ฐ˜ ๋ณ‘ํ•ฉ์„ ์‚ฌ์šฉํ•˜์„ธ์š”.

class Solution {
public:
    vector merge(vector& nums1, int m, vector& nums2, int n) {
        // Copy nums2 into the tail of nums1
        for (int i = m; i  nums1[j + 1]) {
                    swap(nums1[j], nums1[j + 1]);
                }
            }
        }
        return nums1;
    }
};

Approach: ์›ํ•˜์ง€ ์•Š๋Š” ๊ฐ’์„ ์ œ์ž๋ฆฌ์—์„œ ๋ฎ์–ด์“ฐ๊ธฐ ์œ„ํ•ด ํฌ์ธํ„ฐ(idx)๋ฅผ ์ž‘์„ฑํ•ฉ๋‹ˆ๋‹ค.

Approach: Remove Element

Key Learning: ์œ ์ง€ํ•ด์•ผ ํ•  ์š”์†Œ๋“ค์„ ๋ฎ์–ด์“ฐ๊ณ  ์ƒˆ๋กœ์šด ๊ธธ์ด๋ฅผ ๋ฐ˜ํ™˜ํ•ฉ๋‹ˆ๋‹ค.

class Solution {
public:
    int removeElement(vector& nums, int val) {
        int idx = 0;
        for (int i = 0; i & nums) {
        if (nums.empty()) return 0;
        int idx = 1;
        for (int i = 1; i < nums.size(); ++i) {
            if (nums[i] != nums[i - 1]) {
                nums[idx++] = nums[i];
            }
        }
        return idx;
    }
};

General Insights

์ดˆ๊ธฐ DSA ๋ฌธ์ œ๋“ค์€ ๋‹จ์ˆœํ•ด ๋ณด์ผ ์ˆ˜ ์žˆ์ง€๋งŒ, ํ•„์ˆ˜์ ์ธ ์Šต๊ด€์„ ๊ธฐ๋ฅด๋Š” ๋ฐ ๋„์›€์ด ๋ฉ๋‹ˆ๋‹ค:

  • ์ œ์ž๋ฆฌ(inโ€‘place) ์‚ฌ๊ณ 
  • ์ถ”๊ฐ€ ๋ฉ”๋ชจ๋ฆฌ ์ตœ์†Œํ™”
  • ์žฌ์‚ฌ์šฉ ๊ฐ€๋Šฅํ•œ ํŒจํ„ด ์ธ์‹

์ด ๋„์ „์€ ์†๋„์— ๊ด€ํ•œ ๊ฒƒ์ด ์•„๋‹ˆ๋ผ, ๊พธ์ค€ํ•œ ํ–ฅ์ƒ์— ๊ด€ํ•œ ๊ฒƒ์ž…๋‹ˆ๋‹ค.

Next Target

๐Ÿ“ Next Target: Topโ€ฏ150 ๋ฌธ์ œ๋ฅผ ๊ณ„์† ์ง„ํ–‰ํ•ฉ๋‹ˆ๋‹ค.

์—ฌ๋Ÿฌ๋ถ„๋„ DSA๋ฅผ ๊ณต๋ถ€ํ•˜๊ฑฐ๋‚˜ ๋ฌธ์ œ ํ•ด๊ฒฐ ์ผ๊ด€์„ฑ์„ ํ‚ค์šฐ๊ณ  ์žˆ๋‹ค๋ฉด, ํ•จ๊ป˜ ์„ฑ์žฅํ•ด์š”.

Connect

ํ•œ ๋ฒˆ์— ํ•˜๋‚˜์˜ ๋ฌธ์ œ. ๊ฐ•๋„๋ณด๋‹ค ์ผ๊ด€์„ฑ์„ ์ค‘์‹œํ•ฉ๋‹ˆ๋‹ค.

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