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"title": "Count Ways To Build Good Strings",
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"content": "<p>Given the integers <code>zero</code>, <code>one</code>, <code>low</code>, and <code>high</code>, we can construct a string by starting with an empty string, and then at each step perform either of the following:</p>\n\n<ul>\n\t<li>Append the character <code>'0'</code> <code>zero</code> times.</li>\n\t<li>Append the character <code>'1'</code> <code>one</code> times.</li>\n</ul>\n\n<p>This can be performed any number of times.</p>\n\n<p>A <strong>good</strong> string is a string constructed by the above process having a <strong>length</strong> between <code>low</code> and <code>high</code> (<strong>inclusive</strong>).</p>\n\n<p>Return <em>the number of <strong>different</strong> good strings that can be constructed satisfying these properties.</em> Since the answer can be large, return it <strong>modulo</strong> <code>10<sup>9</sup> + 7</code>.</p>\n\n<p> </p>\n<p><strong class=\"example\">Example 1:</strong></p>\n\n<pre>\n<strong>Input:</strong> low = 3, high = 3, zero = 1, one = 1\n<strong>Output:</strong> 8\n<strong>Explanation:</strong> \nOne possible valid good string is "011". \nIt can be constructed as follows: "" -> "0" -> "01" -> "011". \nAll binary strings from "000" to "111" are good strings in this example.\n</pre>\n\n<p><strong class=\"example\">Example 2:</strong></p>\n\n<pre>\n<strong>Input:</strong> low = 2, high = 3, zero = 1, one = 2\n<strong>Output:</strong> 5\n<strong>Explanation:</strong> The good strings are "00", "11", "000", "110", and "011".\n</pre>\n\n<p> </p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>1 <= low <= high <= 10<sup>5</sup></code></li>\n\t<li><code>1 <= zero, one <= low</code></li>\n</ul>\n",
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"code": "class Solution(object):\n def countGoodStrings(self, low, high, zero, one):\n \"\"\"\n :type low: int\n :type high: int\n :type zero: int\n :type one: int\n :rtype: int\n \"\"\"\n ",
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"code": "/**\n * @param {number} low\n * @param {number} high\n * @param {number} zero\n * @param {number} one\n * @return {number}\n */\nvar countGoodStrings = function(low, high, zero, one) {\n \n};",
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"code": "class Solution {\n\n /**\n * @param Integer $low\n * @param Integer $high\n * @param Integer $zero\n * @param Integer $one\n * @return Integer\n */\n function countGoodStrings($low, $high, $zero, $one) {\n \n }\n}",
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"code": "# @param {Integer} low\n# @param {Integer} high\n# @param {Integer} zero\n# @param {Integer} one\n# @return {Integer}\ndef count_good_strings(low, high, zero, one)\n \nend",
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