{"id":2544,"date":"2022-03-28T22:13:29","date_gmt":"2022-03-28T14:13:29","guid":{"rendered":"https:\/\/www.zeroheart.xyz\/wordpress\/?p=2544"},"modified":"2022-03-28T22:59:39","modified_gmt":"2022-03-28T14:59:39","slug":"dp%e7%ac%ac%e4%ba%94%e5%a4%a9","status":"publish","type":"post","link":"https:\/\/www.zeroheart.xyz\/wordpress\/?p=2544","title":{"rendered":"dp\u7b2c\u4e94\u5929"},"content":{"rendered":"\n

\u8fdb\u5ea6\u6709\u4e9b\u843d\u540e\u4e86\u3002\u3002<\/p>\n\n\n\n

\u300c\u52a8\u6001\u89c4\u5212\u300d – \u5b66\u4e60\u8ba1\u5212 – \u529b\u6263\uff08LeetCode\uff09\u5168\u7403\u6781\u5ba2\u631a\u7231\u7684\u6280\u672f\u6210\u957f\u5e73\u53f0 (leetcode-cn.com)<\/a><\/p>\n\n\n\n

53. \u6700\u5927\u5b50\u6570\u7ec4\u548c<\/a><\/p>\n\n\n\n

\u8fd9\u9898\u662f\u7b80\u5355\u5e38\u6570\u7ea7\u522b\u7684dp\uff0c\u6bd4\u6253\u5bb6\u52ab\u820d\u8fd8\u4f4e\u4e00\u7ea7\uff0c\u4e00\u4e0b\u6ca1\u53cd\u5e94\u8fc7\u6765\u3002\u3002<\/p>\n\n\n\n


\/**
<\/em> 53. \u6700\u5927\u5b50\u6570\u7ec4\u548c
<\/em> \u7ed9\u4f60\u4e00\u4e2a\u6574\u6570\u6570\u7ec4 nums \uff0c\u8bf7\u4f60\u627e\u51fa\u4e00\u4e2a\u5177\u6709\u6700\u5927\u548c\u7684\u8fde\u7eed\u5b50\u6570\u7ec4\uff08\u5b50\u6570\u7ec4\u6700\u5c11\u5305\u542b\u4e00\u4e2a\u5143\u7d20\uff09\uff0c\u8fd4\u56de\u5176\u6700\u5927\u548c\u3002
<\/em>
<\/em> \u5b50\u6570\u7ec4 \u662f\u6570\u7ec4\u4e2d\u7684\u4e00\u4e2a\u8fde\u7eed\u90e8\u5206\u3002
<\/em>
<\/em>
<\/em>
<\/em> \u793a\u4f8b 1\uff1a
<\/em>
<\/em> \u8f93\u5165\uff1anums = [-2,1,-3,4,-1,2,1,-5,4]
<\/em> \u8f93\u51fa\uff1a6
<\/em> \u89e3\u91ca\uff1a\u8fde\u7eed\u5b50\u6570\u7ec4 [4,-1,2,1] \u7684\u548c\u6700\u5927\uff0c\u4e3a 6 \u3002
<\/em> \u793a\u4f8b 2\uff1a
<\/em>
<\/em> \u8f93\u5165\uff1anums = [1]
<\/em> \u8f93\u51fa\uff1a1
<\/em> \u793a\u4f8b 3\uff1a
<\/em>
<\/em> \u8f93\u5165\uff1anums = [5,4,-1,7,8]
<\/em> \u8f93\u51fa\uff1a23
<\/em>
<\/em>
<\/em> \u63d0\u793a\uff1a
<\/em>
<\/em> 1 <= nums.length <= 10^5
<\/em> -10^4 <= nums[i] <= 10^4
<\/em>
<\/em>
<\/em> * <\/em>@author <\/em><\/strong>zeroheart
<\/em> *
<\/em> *\/
<\/em>public class Question53 {

    public int maxSubArray(int[] nums) {
        int len = nums.length;
        int max = nums[0];
        int pre = 0;
        for(int i = 0; i<len; i++){
            \/\/ \u65b9\u7a0b\u8981\u8003\u8651\u597d\uff0c\u8fd9\u4e2a\u662f\u5e38\u6570\u7ea7\u522b\u7684dp, pre = Math.max(nums[i], pre+nums[i]); \u4e0d\u662f\u6570\u7ec4\u7ea7\u522b\u7684dp[]\uff0c\u4e0d\u540c\u4e8e\u7b80\u5355\u7248\u672c\u7684\u6253\u5bb6\u52ab\u820d
            pre = Math.max<\/em>(nums[i], pre+nums[i]);
            max = Math.max<\/em>(pre, max);
        }
        return max;
    }

    public static void main(String[] args) {

    }
}<\/pre>\n\n\n\n
918. \u73af\u5f62\u5b50\u6570\u7ec4\u7684\u6700\u5927\u548c<\/a><\/p>\n\n\n\n
\u8fd9\u9898\u9700\u8981\u6280\u5de7\uff0c\u5206\u4e24\u79cd\u60c5\u51b5\uff0c\u4e00\u79cd\u662f\u4e0a\u9762\u9898\u76ee\u7684\u4f8b\u5b50\uff0c\u4e00\u79cd\u60c5\u51b5\u662f\u6210\u73af\u4e86\uff0c\u9700\u8981\u4f7f\u7528total-min\u6765\u7b97\u6700\u5927\uff0c\u540c\u65f6\u8003\u8651max<=0\u7684\u8bdd\uff0c\u6570\u7ec4\u90fd\u662f\u8d1f\u6570\uff0ctotal==min\uff0c\u8fd4\u56demax\u5373\u53ef\u3002<\/mark><\/p>\n\n\n\n
\/**
<\/em> 918. \u73af\u5f62\u5b50\u6570\u7ec4\u7684\u6700\u5927\u548c
<\/em> \u7ed9\u5b9a\u4e00\u4e2a\u957f\u5ea6\u4e3a n \u7684\u73af\u5f62\u6574\u6570\u6570\u7ec4 nums \uff0c\u8fd4\u56de nums \u7684\u975e\u7a7a \u5b50\u6570\u7ec4 \u7684\u6700\u5927\u53ef\u80fd\u548c \u3002
<\/em>
<\/em> \u73af\u5f62\u6570\u7ec4 \u610f\u5473\u7740\u6570\u7ec4\u7684\u672b\u7aef\u5c06\u4f1a\u4e0e\u5f00\u5934\u76f8\u8fde\u5448\u73af\u72b6\u3002\u5f62\u5f0f\u4e0a\uff0c nums[i] \u7684\u4e0b\u4e00\u4e2a\u5143\u7d20\u662f nums[(i + 1) % n] \uff0c nums[i] \u7684\u524d\u4e00\u4e2a\u5143\u7d20\u662f nums[(i - 1 + n) % n] \u3002
<\/em>
<\/em> \u5b50\u6570\u7ec4 \u6700\u591a\u53ea\u80fd\u5305\u542b\u56fa\u5b9a\u7f13\u51b2\u533a nums \u4e2d\u7684\u6bcf\u4e2a\u5143\u7d20\u4e00\u6b21\u3002\u5f62\u5f0f\u4e0a\uff0c\u5bf9\u4e8e\u5b50\u6570\u7ec4 nums[i], nums[i + 1], ..., nums[j] \uff0c\u4e0d\u5b58\u5728 i <= k1, k2 <= j \u5176\u4e2d k1 % n == k2 % n \u3002
<\/em>
<\/em>
<\/em>
<\/em> \u793a\u4f8b 1\uff1a
<\/em>
<\/em> \u8f93\u5165\uff1anums = [1,-2,3,-2]
<\/em> \u8f93\u51fa\uff1a3
<\/em> \u89e3\u91ca\uff1a\u4ece\u5b50\u6570\u7ec4 [3] \u5f97\u5230\u6700\u5927\u548c 3
<\/em> \u793a\u4f8b 2\uff1a
<\/em>
<\/em> \u8f93\u5165\uff1anums = [5,-3,5]
<\/em> \u8f93\u51fa\uff1a10
<\/em> \u89e3\u91ca\uff1a\u4ece\u5b50\u6570\u7ec4 [5,5] \u5f97\u5230\u6700\u5927\u548c 5 + 5 = 10
<\/em> \u793a\u4f8b 3\uff1a
<\/em>
<\/em> \u8f93\u5165\uff1anums = [3,-2,2,-3]
<\/em> \u8f93\u51fa\uff1a3
<\/em> \u89e3\u91ca\uff1a\u4ece\u5b50\u6570\u7ec4 [3] \u548c [3,-2,2] \u90fd\u53ef\u4ee5\u5f97\u5230\u6700\u5927\u548c 3
<\/em>
<\/em>
<\/em> \u63d0\u793a\uff1a
<\/em>
<\/em> n == nums.length
<\/em> 1 <= n <= 3 * 104
<\/em> -3 * 10^4 <= nums[i] <= 3 * 10^4
<\/em>
<\/em> * <\/em>@author <\/em><\/strong>zeroheart
<\/em> *
<\/em> *\/
<\/em>public class Question918 {

    public int maxSubarraySumCircular(int[] nums) {
        \/\/ \u8fd9\u6837\u5199\u7684\u95ee\u9898\u662f\u53ef\u80fd\u53d6\u5230\u4e24\u6b21\u9996\u4f4d\u7684\u6570\u5b57
\/\/        int len = nums.length * 2 -1;
\/\/        int pre = 0;
\/\/        int max = nums[0];
\/\/        for(int i = 0; i<len; i++){
\/\/            int x = i % nums.length;
\/\/            pre = Math.max(nums[x], pre + nums[x]);
\/\/            max = Math.max(max, pre);
\/\/        }
\/\/        return max;



        \/\/ \u8fd9\u9898\u7684\u6280\u5de7\u662f\uff0c\u4e0d\u6210\u73af\u6700\u5927\u7684 \u548c \u6240\u6709\u6570\u5b57\u53ea\u548c-\u4e0d\u6210\u73af\u6700\u5c0f\u7684 \u6bd4\u5927\u5c0f

        int len = nums.length;
        int pre = 0;
        int max = nums[0];
        int minPre = 0;
        int min = nums[0];
        int total = 0;
        for(int i = 0; i<len; i++){
            pre = Math.max<\/em>(nums[i], pre + nums[i]);
            max = Math.max<\/em>(max, pre);

            minPre = Math.min<\/em>(nums[i], minPre + nums[i]);
            min = Math.min<\/em>(min, minPre);

            total += nums[i];
        }

        \/\/ \u6700\u540e\u8fd8\u6709\u4e00\u70b9\u5904\u7406\uff0cmax<=0\u7684\u8bdd\u76f4\u63a5\u8fd4\u56demax\uff0c\u56e0\u4e3atotal==min\uff0ctotal-min = 0
        return max > 0 ? Math.max<\/em>(max, total - min) : max;

    }

    public static void main(String[] args) {

    }
}<\/pre>\n","protected":false},"excerpt":{"rendered":"
\u8fdb\u5ea6\u6709\u4e9b\u843d\u540e\u4e86\u3002\u3002 \u300c\u52a8\u6001\u89c4\u5212\u300d – \u5b66\u4e60\u8ba1\u5212 – \u529b\u6263\uff08LeetCode\uff09\u5168\u7403\u6781\u5ba2\u631a […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[155],"tags":[158],"_links":{"self":[{"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2544"}],"collection":[{"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2544"}],"version-history":[{"count":8,"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2544\/revisions"}],"predecessor-version":[{"id":2552,"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/2544\/revisions\/2552"}],"wp:attachment":[{"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2544"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2544"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.zeroheart.xyz\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2544"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}