leetcode-problemset/leetcode/originData/count-collisions-on-a-road.json

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            "title": "Count Collisions on a Road",
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            "content": "<p>There are <code>n</code> cars on an infinitely long road. The cars are numbered from <code>0</code> to <code>n - 1</code> from left to right and each car is present at a <strong>unique</strong> point.</p>\n\n<p>You are given a <strong>0-indexed</strong> string <code>directions</code> of length <code>n</code>. <code>directions[i]</code> can be either <code>&#39;L&#39;</code>, <code>&#39;R&#39;</code>, or <code>&#39;S&#39;</code> denoting whether the <code>i<sup>th</sup></code> car is moving towards the <strong>left</strong>, towards the <strong>right</strong>, or <strong>staying</strong> at its current point respectively. Each moving car has the <strong>same speed</strong>.</p>\n\n<p>The number of collisions can be calculated as follows:</p>\n\n<ul>\n\t<li>When two cars moving in <strong>opposite</strong> directions collide with each other, the number of collisions increases by <code>2</code>.</li>\n\t<li>When a moving car collides with a stationary car, the number of collisions increases by <code>1</code>.</li>\n</ul>\n\n<p>After a collision, the cars involved can no longer move and will stay at the point where they collided. Other than that, cars cannot change their state or direction of motion.</p>\n\n<p>Return <em>the <strong>total number of collisions</strong> that will happen on the road</em>.</p>\n\n<p>&nbsp;</p>\n<p><strong class=\"example\">Example 1:</strong></p>\n\n<pre>\n<strong>Input:</strong> directions = &quot;RLRSLL&quot;\n<strong>Output:</strong> 5\n<strong>Explanation:</strong>\nThe collisions that will happen on the road are:\n- Cars 0 and 1 will collide with each other. Since they are moving in opposite directions, the number of collisions becomes 0 + 2 = 2.\n- Cars 2 and 3 will collide with each other. Since car 3 is stationary, the number of collisions becomes 2 + 1 = 3.\n- Cars 3 and 4 will collide with each other. Since car 3 is stationary, the number of collisions becomes 3 + 1 = 4.\n- Cars 4 and 5 will collide with each other. After car 4 collides with car 3, it will stay at the point of collision and get hit by car 5. The number of collisions becomes 4 + 1 = 5.\nThus, the total number of collisions that will happen on the road is 5. \n</pre>\n\n<p><strong class=\"example\">Example 2:</strong></p>\n\n<pre>\n<strong>Input:</strong> directions = &quot;LLRR&quot;\n<strong>Output:</strong> 0\n<strong>Explanation:</strong>\nNo cars will collide with each other. Thus, the total number of collisions that will happen on the road is 0.</pre>\n\n<p>&nbsp;</p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>1 &lt;= directions.length &lt;= 10<sup>5</sup></code></li>\n\t<li><code>directions[i]</code> is either <code>&#39;L&#39;</code>, <code>&#39;R&#39;</code>, or <code>&#39;S&#39;</code>.</li>\n</ul>\n",
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                    "code": "class Solution(object):\n    def countCollisions(self, directions):\n        \"\"\"\n        :type directions: str\n        :rtype: int\n        \"\"\"\n        ",
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                    "code": "/**\n * @param {string} directions\n * @return {number}\n */\nvar countCollisions = function(directions) {\n    \n};",
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                    "code": "# @param {String} directions\n# @return {Integer}\ndef count_collisions(directions)\n    \nend",
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            "hints": [
                "In what circumstances does a moving car not collide with another car?",
                "If we disregard the moving cars that do not collide with another car, what does each moving car contribute to the answer?",
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