World's Easiest  Solution 100% beats
Intuition \uD83E\uDDE0\nThe problem can be visualized as a block alignment game, where the blocks in the start string need to be rearranged to match the target 
# Intuition \uD83E\uDDE0\nThe problem can be visualized as a **block alignment game**, where the blocks in the `start` string need to be rearranged to match the `target` string. The blocks have special movement rules:\n\n- **`L` Block**: Moves only **left** \u2B05\uFE0F.\n- **`R` Block**: Moves only **right** \u27A1\uFE0F.\n- **`_` (Blank)**: Represents an empty space where blocks can move but doesn\'t move itself.\n\nWe must ensure:\n1. The characters in `start` and `target` match when ignoring the blanks.\n2. The movement constraints of `L` and `R` are followed correctly.\n\n---\n\n# Approach \uD83D\uDEE0\uFE0F\n\n## Step 1: Use Two Pointers \uD83D\uDD00\nWe use two pointers:\n- `startIndex` to traverse the `start` string.\n- `targetIndex` to traverse the `target` string.\n\n---\n\n### Step 2: Skip Blank Spaces \uD83D\uDE80\n- While traversing, **skip all `_`** in both strings because blanks don\'t contribute to the alignment.\n- Focus only on the `L` and `R` blocks.\n\n---\n\n### Step 3: Compare Characters \uD83E\uDDE9\n- After skipping blanks, compare the characters at `start[startIndex]` and `target[targetIndex]`:\n  - If they **don\u2019t match**, transformation is not possible. \u274C\n  - If they match, move forward to check movement rules.\n\n---\n\n### Step 4: Verify Movement Rules \uD83D\uDCDC\n1. **For `L` Blocks**:\n   - The block in `start` **must not move right** (it can only move left).\n   - If the block\'s current position (`startIndex`) is **less than** its position in `target` (`targetIndex`), return `false`.\n\n2. **For `R` Blocks**:\n   - The block in `start` **must not move left** (it can only move right).\n   - If the block\'s current position (`startIndex`) is **greater than** its position in `target` (`targetIndex`), return `false`.\n\n---\n\n### Step 5: Handle Remaining Characters \uD83D\uDD04\n- After one pointer finishes, check if the other string contains only blanks (`_`).\n- If not, return `false` as the strings cannot align.\n\n---\n\n# Complexity \uD83D\uDCCA\n\n- **Time Complexity**:  \n  Traverses both strings once, skipping blanks and verifying characters.  \n  **$$O(n)$$**\n\n- **Space Complexity**:  \n  Uses constant space for variables.  \n  **$$O(1)$$**\n\n---\n![DALL\xB7E 2024-11-30 07.03.29 - A cute animated character giving an upvote gesture with a big smile, surrounded by small colorful stars and hearts. The character is small and round, .webp](https://assets.leetcode.com/users/images/894f5749-b47c-490a-9020-1eb6666c47d6_1733362452.4242637.webp)\n\n```cpp []\nclass Solution {\npublic:\n    bool canChange(string start, string target) {\n        int L = 0;\n        int M = 0;\n        int n = start.length();\n        int tarspace = 0;\n        int staspace = 0;\n\n        while (L < n && M < n) {\n            while (L < n && target[L] == \'_\') {\n                tarspace++;\n                L++;\n            }\n            while (M < n && start[M] == \'_\') {\n                M++;\n                staspace++;\n            }\n\n            if (L < n && M < n) {\n                if (target[L] != start[M]) {\n                    return false;\n                }\n                if (target[L] == \'L\') {\n                    if (tarspace > staspace)\n                        return false;\n                } else if (staspace > tarspace) {\n                    return false;\n                }\n                L++;\n                M++;\n            }\n        }\n\n        // Check remaining characters\n        while (L < n) {\n            if (target[L] != \'_\')\n                return false;\n            L++;\n        }\n        while (M < n) {\n            if (start[M] != \'_\')\n                return false;\n            M++;\n        }\n\n        return true;\n    }\n};\n\nvoid IO() {\n    ios::sync_with_stdio(false);\n    cin.tie(0);\n}\n\n```\n```Python3 []\nclass Solution(object):\n    def canChange(self, start, target):\n        """\n        :type start: str\n        :type target: str\n        :rtype: bool\n        """\n        L = 0\n        M = 0\n        n = len(start)\n        tarspace = 0\n        staspace = 0\n\n        while L < n and M < n:\n            while L < n and target[L] == \'_\':\n                tarspace += 1\n                L += 1\n            while M < n and start[M] == \'_\':\n                M += 1\n                staspace += 1\n\n            if L < n and M < n:\n                if target[L] != start[M]:\n                    return False\n                if target[L] == \'L\':\n                    if tarspace > staspace:\n                        return False\n                elif staspace > tarspace:\n                    return False\n                L += 1\n                M += 1\n\n        # Check remaining characters\n        while L < n:\n            if target[L] != \'_\':\n                return False\n            L += 1\n        while M < n:\n            if start[M] != \'_\':\n                return False\n            M += 1\n\n        return True\n```\n```java []\nclass Solution {\n    public boolean canChange(String start, String target) {\n        int L = 0, M = 0;\n        int n = start.length();\n        int tarSpace = 0, staSpace = 0;\n\n        while (L < n && M < n) {\n            while (L < n && target.charAt(L) == \'_\') {\n                tarSpace++;\n                L++;\n            }\n            while (M < n && start.charAt(M) == \'_\') {\n                staSpace++;\n                M++;\n            }\n\n            if (L < n && M < n) {\n                if (target.charAt(L) != start.charAt(M)) {\n                    return false;\n                }\n                if (target.charAt(L) == \'L\') {\n                    if (tarSpace > staSpace) {\n                        return false;\n                    }\n                } else if (staSpace > tarSpace) {\n                    return false;\n                }\n                L++;\n                M++;\n            }\n        }\n\n        // Check remaining characters\n        while (L < n) {\n            if (target.charAt(L) != \'_\') {\n                return false;\n            }\n            L++;\n        }\n        while (M < n) {\n            if (start.charAt(M) != \'_\') {\n                return false;\n            }\n            M++;\n        }\n\n        return true;\n    }\n}\n```\n```C# []\npublic class Solution {\n    public bool CanChange(string start, string target) {\n        int L = 0, M = 0;\n        int n = start.Length;\n        int tarSpace = 0, staSpace = 0;\n\n        while (L < n && M < n) {\n            while (L < n && target[L] == \'_\') {\n                tarSpace++;\n                L++;\n            }\n            while (M < n && start[M] == \'_\') {\n                staSpace++;\n                M++;\n            }\n\n            if (L < n && M < n) {\n                if (target[L] != start[M]) {\n                    return false;\n                }\n                if (target[L] == \'L\') {\n                    if (tarSpace > staSpace) {\n                        return false;\n                    }\n                } else if (staSpace > tarSpace) {\n                    return false;\n                }\n                L++;\n                M++;\n            }\n        }\n\n        // Check remaining characters\n        while (L < n) {\n            if (target[L] != \'_\') {\n                return false;\n            }\n            L++;\n        }\n        while (M < n) {\n            if (start[M] != \'_\') {\n                return false;\n            }\n            M++;\n        }\n\n        return true;\n    }\n}\n\n```\n```Java_Script []\n/**\n * @param {string} start\n * @param {string} target\n * @return {boolean}\n */\nvar canChange = function(start, target) {\n    let L = 0, M = 0;\n    const n = start.length;\n    let tarSpace = 0, staSpace = 0;\n\n    while (L < n && M < n) {\n        while (L < n && target[L] === \'_\') {\n            tarSpace++;\n            L++;\n        }\n        while (M < n && start[M] === \'_\') {\n            staSpace++;\n            M++;\n        }\n\n        if (L < n && M < n) {\n            if (target[L] !== start[M]) {\n                return false;\n            }\n            if (target[L] === \'L\') {\n                if (tarSpace > staSpace) {\n                    return false;\n                }\n            } else if (staSpace > tarSpace) {\n                return false;\n            }\n            L++;\n            M++;\n        }\n    }\n\n    // Check remaining characters\n    while (L < n) {\n        if (target[L] !== \'_\') {\n            return false;\n        }\n        L++;\n    }\n    while (M < n) {\n        if (start[M] !== \'_\') {\n            return false;\n        }\n        M++;\n    }\n\n    return true;\n};\n```\n``` Rust []\nimpl Solution {\n    pub fn can_change(start: String, target: String) -> bool {\n        let start: Vec<char> = start.chars().collect();\n        let target: Vec<char> = target.chars().collect();\n        let mut l = 0;\n        let mut m = 0;\n        let n = start.len();\n        let mut tar_space = 0;\n        let mut sta_space = 0;\n\n        while l < n && m < n {\n            while l < n && target[l] == \'_\' {\n                tar_space += 1;\n                l += 1;\n            }\n            while m < n && start[m] == \'_\' {\n                sta_space += 1;\n                m += 1;\n            }\n\n            if l < n && m < n {\n                if target[l] != start[m] {\n                    return false;\n                }\n                if target[l] == \'L\' {\n                    if tar_space > sta_space {\n                        return false;\n                    }\n                } else if sta_space > tar_space {\n                    return false;\n                }\n                l += 1;\n                m += 1;\n            }\n        }\n\n        // Check remaining characters\n        while l < n {\n            if target[l] != \'_\' {\n                return false;\n            }\n            l += 1;\n        }\n        while m < n {\n            if start[m] != \'_\' {\n                return false;\n            }\n            m += 1;\n        }\n\n        true\n    }\n}\n\n```\n
['C++', 'Java', 'Python3', 'Rust', 'JavaScript', 'C#']