{"id":26811,"date":"2017-12-24T15:29:48","date_gmt":"2017-12-24T09:59:48","guid":{"rendered":"https:\/\/www.wikitechy.com\/technology\/?p=26811"},"modified":"2017-12-24T15:33:45","modified_gmt":"2017-12-24T10:03:45","slug":"java-programming-largest-sum-contiguous-subarray","status":"publish","type":"post","link":"https:\/\/www.wikitechy.com\/technology\/java-programming-largest-sum-contiguous-subarray\/","title":{"rendered":"Java Programming &#8211; Largest Sum Contiguous Subarray"},"content":{"rendered":"<p>Write an efficient Java program to find the sum of contiguous subarray within a one-dimensional array of numbers which has the largest sum.<\/p>\n<p><img fetchpriority=\"high\" decoding=\"async\" class=\"alignleft size-full wp-image-26804\" src=\"https:\/\/www.wikitechy.com\/technology\/wp-content\/uploads\/2017\/06\/kadane-Algorithm.png\" alt=\"kadane Algorithm\" width=\"564\" height=\"345\" srcset=\"https:\/\/www.wikitechy.com\/technology\/wp-content\/uploads\/2017\/06\/kadane-Algorithm.png 564w, https:\/\/www.wikitechy.com\/technology\/wp-content\/uploads\/2017\/06\/kadane-Algorithm-300x184.png 300w\" sizes=\"(max-width: 564px) 100vw, 564px\" \/><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><strong>Kadane\u2019s Algorithm:<\/strong><\/p>\n<pre>Initialize:\r\n    max_so_far = 0\r\n    max_ending_here = 0\r\n\r\nLoop for each element of the array\r\n  (a) max_ending_here = max_ending_here + a[i]\r\n  (b) if(max_ending_here &lt; 0)\r\n            max_ending_here = 0\r\n  (c) if(max_so_far &lt; max_ending_here)\r\n            max_so_far = max_ending_here\r\nreturn max_so_far\r\n<\/pre>\n[ad type=&#8221;banner&#8221;]\n<p><strong>Explanation:<\/strong><br \/>\nSimple idea of the Kadane&#8217;s algorithm is to look for all positive contiguous segments of the array (max_ending_here is used for this). And keep track of maximum sum contiguous segment among all positive segments (max_so_far is used for this). Each time we get a positive sum compare it with max_so_far and update max_so_far if it is greater than max_so_far<\/p>\n<pre>    Lets take the example:\r\n    {-2, -3, 4, -1, -2, 1, 5, -3}\r\n\r\n    max_so_far = max_ending_here = 0\r\n\r\n    for i=0,  a[0] =  -2\r\n    max_ending_here = max_ending_here + (-2)\r\n    Set max_ending_here = 0 because max_ending_here &lt; 0\r\n\r\n    for i=1,  a[1] =  -3\r\n    max_ending_here = max_ending_here + (-3)\r\n    Set max_ending_here = 0 because max_ending_here &lt; 0\r\n\r\n    for i=2,  a[2] =  4\r\n    max_ending_here = max_ending_here + (4)\r\n    max_ending_here = 4\r\n    max_so_far is updated to 4 because max_ending_here greater \r\n    than max_so_far which was 0 till now\r\n\r\n    for i=3,  a[3] =  -1\r\n    max_ending_here = max_ending_here + (-1)\r\n    max_ending_here = 3\r\n\r\n    for i=4,  a[4] =  -2\r\n    max_ending_here = max_ending_here + (-2)\r\n    max_ending_here = 1\r\n\r\n    for i=5,  a[5] =  1\r\n    max_ending_here = max_ending_here + (1)\r\n    max_ending_here = 2\r\n\r\n    for i=6,  a[6] =  5\r\n    max_ending_here = max_ending_here + (5)\r\n    max_ending_here = 7\r\n    max_so_far is updated to 7 because max_ending_here is \r\n    greater than max_so_far\r\n\r\n    for i=7,  a[7] =  -3\r\n    max_ending_here = max_ending_here + (-3)\r\n    max_ending_here = 4\r\n<\/pre>\n<p><strong>Program:<\/strong><\/p>\n<div class=\"responsive-tabs-wrapper\">\n<div class=\"responsive-tabs responsive-tabs--enabled\">\n<div id=\"tablist1-panel1\" class=\"tabcontent responsive-tabs__panel responsive-tabs__panel--active\">\n<p><strong>Output :<\/strong><\/p>\n<pre>Maximum contiguous sum is 7<\/pre>\n[ad type=&#8221;banner&#8221;]\n<p>Above program can be optimized further, if we compare max_so_far with max_ending_here only if max_ending_here is greater than 0.<\/p>\n<div class=\"code-embed-wrapper\"> <div class=\"code-embed-infos\"> <span class=\"code-embed-name\">Java<\/span> <\/div> <pre class=\"language-java code-embed-pre line-numbers\"  data-start=\"1\" data-line-offset=\"0\"><code class=\"language-java code-embed-code\">import java.io.*;<br\/>\/\/ Java program to print largest contiguous array sum<br\/>import java.util.*;<br\/> <br\/>class Kadane<br\/>{<br\/>    public static void main (String[] args)<br\/>    {<br\/>        int [] a = {-2, -3, 4, -1, -2, 1, 5, -3};<br\/>        System.out.println(&quot;Maximum contiguous sum is &quot; +<br\/>                                       maxSubArraySum(a));<br\/>    }<br\/> <br\/>    static int maxSubArraySum(int a[])<br\/>    {<br\/>        int size = a.length;<br\/>        int max_so_far = Integer.MIN_VALUE, max_ending_here = 0;<br\/> <br\/>        for (int i = 0; i &lt; size; i++)<br\/>        {<br\/>            max_ending_here = max_ending_here + a[i];<br\/>            if (max_so_far &lt; max_ending_here)<br\/>                max_so_far = max_ending_here;<br\/>            if (max_ending_here &lt; 0)<br\/>                max_ending_here = 0;<br\/>        }<br\/>        return max_so_far;<br\/>    }<br\/>}<\/code><\/pre> <\/div>\n<p><strong>Time Complexity: <\/strong>O(n)<br \/>\n<strong>Algorithmic Paradigm: <\/strong>Dynamic Programming<\/p>\n<p>&nbsp;<\/p>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Java Programming &#8211; Largest Sum Contiguous Subarray &#8211; Dynamic Programming Write a program to find the sum of contiguous subarray within one-dimensional array<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1,70145],"tags":[79945,73508,72847,79942,72842,72845,70483,72848,72840,72846,72987,72985,72843,72854,72844,72850,72839,79946,79700,78246,79939,79934,79931,78231,79928,79692,79935,79940,79936,79929,79930,79938,77932,79933,79944,79943,72852,72855,79932,79937,79941,78229,72853,72851],"class_list":["post-26811","post","type-post","status-publish","format-standard","hentry","category-coding","category-dynamic-programming","tag-array-find","tag-array-java","tag-concept-of-dynamic-programming","tag-contiguous-sequence","tag-define-dynamic-programming","tag-definition-of-dynamic-programming","tag-dynamic-programming","tag-dynamic-programming-code-generation-algorithm","tag-dynamic-programming-definition","tag-dynamic-programming-in-data-structure","tag-dynamic-programming-in-java","tag-dynamic-programming-java","tag-dynamic-programming-problems","tag-dynamic-programming-set-1","tag-dynamic-programming-software","tag-explain-dynamic-programming","tag-how-to-solve-dynamic-programming-problems","tag-java-find","tag-java-max","tag-java-sum","tag-kadane","tag-kadane-algorithm","tag-kadanes-algorithm","tag-kadanes-algorithm-java","tag-largest-sum-contiguous-subarray","tag-max-java","tag-max-subarray","tag-max-subarray-problem","tag-maximum-product-subarray","tag-maximum-subarray","tag-maximum-subarray-problem","tag-maximum-subarray-sum","tag-maximum-subsequence-sum","tag-maximum-sum-subarray","tag-non-contiguous","tag-php-array-sum","tag-problems-on-dynamic-programming","tag-simple-dynamic-programming-example","tag-subarray","tag-subarray-java","tag-sum-java","tag-sum-sum","tag-types-of-dynamic-programming","tag-youtube-dynamic-programming"],"_links":{"self":[{"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/posts\/26811","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/comments?post=26811"}],"version-history":[{"count":0,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/posts\/26811\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/media?parent=26811"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/categories?post=26811"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.wikitechy.com\/technology\/wp-json\/wp\/v2\/tags?post=26811"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}