{"id":822,"date":"2021-03-04T11:03:49","date_gmt":"2021-03-04T03:03:49","guid":{"rendered":"http:\/\/lonelinerd.com\/?p=822"},"modified":"2021-03-04T11:28:19","modified_gmt":"2021-03-04T03:28:19","slug":"leetcode-677","status":"publish","type":"post","link":"https:\/\/lonelinerd.com\/index.php\/2021\/03\/04\/leetcode-677\/","title":{"rendered":"[LeetCode\u5237\u984c\u7b46\u8a18] 677 – Map Sum Pairs"},"content":{"rendered":"\t\t
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\u984c\u76ee\u63cf\u8ff0\uff1a<\/strong><\/span><\/h4>

Implement the <\/span>MapSum<\/code><\/span> class:<\/span><\/p>

  • MapSum()<\/code><\/span> Initializes the <\/span>MapSum<\/code><\/span> object.<\/span><\/p><\/li>

  • void insert(String key, int val)<\/code><\/span> Inserts the <\/span>key-val<\/code><\/span> pair into the map. If the <\/span>key<\/code><\/span> already existed, the original <\/span>key-value<\/code><\/span> pair will be overridden to the new one.<\/span><\/p><\/li>

  • int sum(string prefix)<\/code><\/span> Returns the sum of all the pairs’ value whose <\/span>key<\/code><\/span> starts with the <\/span>prefix<\/code><\/span>.<\/span><\/p><\/li><\/ul>

    \u00a0<\/p>

    Example 1:<\/span><\/strong><\/span><\/p>

    Input<\/span>
    [\"MapSum\", \"insert\", \"sum\", \"insert\", \"sum\"]<\/span>
    [[], [\"apple\", 3], [\"ap\"], [\"app\", 2], [\"ap\"]]<\/span>
    Output<\/span>
    [null, null, 3, null, 5]<\/span>
    \u200b<\/span>
    Explanation<\/span>
    MapSum mapSum = new MapSum();<\/span>
    mapSum.insert(\"apple\", 3); \u00a0<\/span>
    mapSum.sum(\"ap\"); \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \/\/ return 3 (apple = 3)<\/span>
    mapSum.insert(\"app\", 2); \u00a0 \u00a0<\/span>
    mapSum.sum(\"ap\"); \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \/\/ return 5 (apple + app = 3 + 2 = 5)<\/span><\/pre>
    \u00a0<\/p>
    Constraints:<\/span><\/strong><\/span><\/p>
    • 1 <= key.length, prefix.length <= 50<\/code><\/span><\/p><\/li>
    • key<\/code><\/span> and <\/span>prefix<\/code><\/span> consist of only lowercase English letters.<\/span><\/p><\/li>
    • 1 <= val <= 1000<\/code><\/span><\/p><\/li>
    • At most <\/span>50<\/code><\/span> calls will be made to <\/span>insert<\/code><\/span> and <\/span>sum<\/code><\/span>.<\/span><\/p><\/li><\/ul>\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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      \n\t\t\t\n\t\t\t\t\t\t<\/span>\n\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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      \u4e00\u5237\u984c\u89e3\uff08Trie\uff09\uff1a<\/strong><\/span><\/h4>
      \u00a0 \u00a0 \u00a0 \u00a0 \u9019\u984c\u9700\u8981\u6211\u5011\u53bb\u5beb\u4e00\u500bMapSum\u7684\u985e\uff0c\u9019\u500b\u985e\u9700\u8981\u6211\u5011\u5be6\u73fe\u4e00\u500b\u63d2\u5165\u65b9\u6cd5\uff0c\u5c07\u4e00\u500bstring:int\u7684\u9375\u503c\u5c0d\u653e\u9032\u6578\u64da\u7d50\u69cb\u88e1\uff1b\u53e6\u5916\u5be6\u73fe\u4e00\u500b\u52a0\u7e3d\u7684\u65b9\u6cd5\uff0c\u901a\u904e\u50b3\u5165\u4e00\u500bstring\uff0c\u6aa2\u67e5\u6578\u64da\u7d50\u69cb\u88e1\u4ee5\u9019\u500bstring\u70ba\u524d\u7db4\u7684\u6240\u6709\u9375\uff0c\u4e26\u5c07\u5b83\u5011\u7684\u7e3d\u548c\u52a0\u7e3d\u8d77\u4f86\u3002<\/p>
      \u00a0 \u00a0 \u00a0 \u00a0 \u7b2c\u4e00\u611f\u89ba\u662f\u7528\u5b57\u5178\u53bb\u505a\uff0c\u7562\u7adf\u6709\u9375\u503c\u5c0d\u9019\u500b\u5143\u7d20\u3002\u4f46\u662f\u8a66\u8457\u7528\u5b57\u5178\u5f8c\u767c\u73fe\u4e0d\u592a\u597d\u505a\uff0c\u56e0\u70ba\u9664\u4e86\u63d2\u5165\u9375\u503c\u5c0d\u4ee5\u5916\uff0c\u9084\u9700\u8981\u6aa2\u67e5\u5b57\u7b26\u4e32\u7684\u524d\u7db4\uff0c\u9032\u884c\u524d\u7db4\u7684\u6aa2\u67e5\u6700\u597d\u9084\u662f\u4f7f\u7528Trie\uff08\u5b57\u9996\u6a39\uff09\u4f86\u505a\u6bd4\u8f03\u597d\u3002<\/p>
      \u00a0 \u00a0 \u00a0 \u00a0 \u4f7f\u7528\u5b57\u9996\u6a39\u4f86\u505a\uff0c\u9996\u5148\u8981\u6709\u4e00\u500b\u5b57\u9996\u6a39\u7bc0\u9ede\u7684\u985e\uff0c\u9019\u500b\u985e\u88e1\u8981\u6709\u4e00\u500b\u5305\u542b26\u500b\u5b50\u6bcd\u5b50\u7bc0\u9ede\u7684\u6578\u7d44\uff0c\u4e00\u500bint\u503c\u8a18\u9304insert\u50b3\u9032\u4f86\u7684val\u3002\u5728Insert\u6642\uff0c\u6309\u7167\u5b57\u9996\u6a39\u7684\u4e00\u822c\u904d\u6b77\u65b9\u6cd5\uff0c\u904d\u6b77\u5b57\u7b26\u4e32\u4e2d\u7684\u6240\u6709\u5b57\u7b26\uff0c\u6700\u5f8c\u628a\u503c\u8ce6\u7d66\u5b57\u7b26\u4e32\u7d42\u9ede\u7684\u5b57\u7b26\u7bc0\u9ede\u4e2d\u3002<\/p>
      \u00a0 \u00a0 \u00a0 \u00a0 \u9032\u884c\u52a0\u7e3d\u6642\uff0c\u540c\u6a23\u662f\u5c07\u50b3\u9032\u4f86\u7684prefix\u5f9e\u982d\u904d\u6b77\u5230\u5c3e\u90e8\uff0c\u78ba\u5b9a\u6709\u9019\u500bprefix\u7684\u5b58\u5728\u3002\u7136\u5f8c\u518d\u5c0d\u9019\u500bprefix\u4e0b\u7684\u6240\u6709\u5b57\u6bcd\u7bc0\u9ede\u9032\u884c\u6df1\u5ea6\u512a\u5148\u67e5\u627e\uff0c\u5f97\u5230\u6240\u6709\u4ee5\u9019\u500bprefix\u70ba\u524d\u7db4\u7684\u5b50\u7bc0\u9ede\u7684\u503c\uff0c\u6700\u5f8c\u9032\u884c\u52a0\u7e3d\uff0c\u5f97\u51fa\u7d50\u679c\u3002<\/p>\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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      public<\/span> class<\/span> MapSum<\/span> {<\/span>
      \u200b<\/span>
       \u00a0 \u00a0MapSumNode<\/span> root<\/span>;<\/span>
       \u00a0 \u00a0<\/span>
       \u00a0 \u00a0\/** Initialize your data structure here. *\/<\/span><\/span>
       \u00a0 \u00a0public<\/span> MapSum<\/span>() {<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0root<\/span> =<\/span> new<\/span> MapSumNode<\/span>();<\/span>
       \u00a0  }<\/span>
       \u00a0 \u00a0
      <\/span>    \/\/\u63d2\u5165\u5143\u7d20
       \u00a0 \u00a0public<\/span> void<\/span> Insert<\/span>(string<\/span> key<\/span>, int<\/span> val<\/span>) {<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0MapSumNode<\/span> curr<\/span> =<\/span> root<\/span>;<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0for<\/span>(int<\/span> i<\/span> =<\/span> 0<\/span>; i<\/span> <<\/span> key<\/span>.Length<\/span>; i<\/span>++<\/span>)<\/span>
       \u00a0 \u00a0 \u00a0  {<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0int<\/span> id<\/span> =<\/span> key<\/span>[i<\/span>] -<\/span> 'a'<\/span>;<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0if<\/span>(curr<\/span>.children<\/span>[id<\/span>] ==<\/span> null<\/span>)<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0 \u00a0  {<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0curr<\/span>.children<\/span>[id<\/span>] =<\/span> new<\/span> MapSumNode<\/span>();<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0 \u00a0  }<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0curr<\/span> =<\/span> curr<\/span>.children<\/span>[id<\/span>];<\/span>
       \u00a0 \u00a0 \u00a0  }<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0curr<\/span>.val<\/span> =<\/span> val<\/span>;<\/span>
       \u00a0  }<\/span>
       \u00a0 \u00a0<\/span>
       \u00a0 \u00a0public<\/span> int<\/span> Sum<\/span>(string<\/span> prefix<\/span>) {<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0MapSumNode<\/span> curr<\/span> =<\/span> root<\/span>;<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0\/\/\u9700\u8981\u904d\u6b77\u5230prefix\u7684\u5c3e\u90e8\u4ee5\u78ba\u8a8dprefix\u7684\u5b58\u5728<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0for<\/span>(int<\/span> i<\/span> =<\/span> 0<\/span>; i<\/span> <<\/span> prefix<\/span>.Length<\/span>; i<\/span>++<\/span>)<\/span>
       \u00a0 \u00a0 \u00a0  {<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0int<\/span> id<\/span> =<\/span> prefix<\/span>[i<\/span>] -<\/span> 'a'<\/span>;<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0if<\/span>(curr<\/span>.children<\/span>[id<\/span>] ==<\/span> null<\/span>)<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0 \u00a0  {<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0return<\/span> 0<\/span>;<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0 \u00a0  }<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0curr<\/span> =<\/span> curr<\/span>.children<\/span>[id<\/span>];<\/span>
       \u00a0 \u00a0 \u00a0  }
      <\/span>        \/\/\u7576prefix\u662f\u5b58\u5728\u7684\uff0c\u5c0dprefix\u4e0b\u7684\u6240\u6709\u5305\u542b\u4e86MapSumNode\u7684\u5b50\u7bc0\u9ede\u7684Value\u9032\u884c\u52a0\u7e3d
       \u00a0 \u00a0 \u00a0 \u00a0return<\/span> GetSumDFS<\/span>(curr<\/span>);<\/span>
       \u00a0  }
      <\/span>    \/\/\u52a0\u7e3d
       \u00a0 \u00a0int<\/span> GetSumDFS<\/span>(MapSumNode<\/span> node<\/span>)<\/span>
       \u00a0  {<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0int<\/span> sum<\/span> =<\/span> node<\/span>.val<\/span>;<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0for<\/span>(int<\/span> i<\/span> =<\/span> 0<\/span>; i<\/span> <<\/span> node<\/span>.children<\/span>.Count<\/span>(); i<\/span>++<\/span>)<\/span>
       \u00a0 \u00a0 \u00a0  {<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0if<\/span>(node<\/span>.children<\/span>[i<\/span>] !=<\/span> null<\/span>)<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0 \u00a0  {<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0 \u00a0sum<\/span> +=<\/span> GetSumDFS<\/span>(node<\/span>.children<\/span>[i<\/span>]);<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0 \u00a0  }<\/span>
       \u00a0 \u00a0 \u00a0  }<\/span>
       \u00a0 \u00a0 \u00a0 \u00a0return<\/span> sum<\/span>;<\/span>
       \u00a0  }<\/span>
      }<\/span>
      \u200b<\/span>
      public<\/span> class<\/span> MapSumNode<\/span><\/span>
      {<\/span>
       \u00a0 \u00a0public<\/span> MapSumNode<\/span>[] children<\/span> =<\/span> new<\/span> MapSumNode<\/span>[26<\/span>];<\/span>
       \u00a0 \u00a0public<\/span> int<\/span> val<\/span>;<\/span>
       \u00a0 \u00a0public<\/span> MapSumNode<\/span>(){}<\/span>
      }<\/span><\/pre>\t\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"
      \u984c\u76ee\u63cf\u8ff0\uff1a Implement the MapSum class: MapSum() Initializes  …<\/p>\n
        [LeetCode\u5237\u984c\u7b46\u8a18] 677 – Map Sum Pairs<\/span> Read More »<\/a><\/p>\n","protected":false},"author":1,"featured_media":570,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,16],"tags":[],"class_list":["post-822","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-programming-notes","category-leetcodes"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"https:\/\/lonelinerd.com\/wp-content\/uploads\/2021\/02\/FeatureCover_LeetCoding.png","_links":{"self":[{"href":"https:\/\/lonelinerd.com\/index.php\/wp-json\/wp\/v2\/posts\/822","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lonelinerd.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lonelinerd.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lonelinerd.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lonelinerd.com\/index.php\/wp-json\/wp\/v2\/comments?post=822"}],"version-history":[{"count":8,"href":"https:\/\/lonelinerd.com\/index.php\/wp-json\/wp\/v2\/posts\/822\/revisions"}],"predecessor-version":[{"id":831,"href":"https:\/\/lonelinerd.com\/index.php\/wp-json\/wp\/v2\/posts\/822\/revisions\/831"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/lonelinerd.com\/index.php\/wp-json\/wp\/v2\/media\/570"}],"wp:attachment":[{"href":"https:\/\/lonelinerd.com\/index.php\/wp-json\/wp\/v2\/media?parent=822"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lonelinerd.com\/index.php\/wp-json\/wp\/v2\/categories?post=822"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lonelinerd.com\/index.php\/wp-json\/wp\/v2\/tags?post=822"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}