{ "data": { "question": { "questionId": "2133", "questionFrontendId": "2023", "boundTopicId": null, "title": "Number of Pairs of Strings With Concatenation Equal to Target", "titleSlug": "number-of-pairs-of-strings-with-concatenation-equal-to-target", "content": "

Given an array of digit strings nums and a digit string target, return the number of pairs of indices (i, j) (where i != j) such that the concatenation of nums[i] + nums[j] equals target.

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Example 1:

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\nInput: nums = ["777","7","77","77"], target = "7777"\nOutput: 4\nExplanation: Valid pairs are:\n- (0, 1): "777" + "7"\n- (1, 0): "7" + "777"\n- (2, 3): "77" + "77"\n- (3, 2): "77" + "77"\n
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Example 2:

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\nInput: nums = ["123","4","12","34"], target = "1234"\nOutput: 2\nExplanation: Valid pairs are:\n- (0, 1): "123" + "4"\n- (2, 3): "12" + "34"\n
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Example 3:

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\nInput: nums = ["1","1","1"], target = "11"\nOutput: 6\nExplanation: Valid pairs are:\n- (0, 1): "1" + "1"\n- (1, 0): "1" + "1"\n- (0, 2): "1" + "1"\n- (2, 0): "1" + "1"\n- (1, 2): "1" + "1"\n- (2, 1): "1" + "1"\n
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Constraints:

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Compiled with clang 11 using the latest C++ 17 standard.

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Your code is compiled with level two optimization (-O2). AddressSanitizer is also enabled to help detect out-of-bounds and use-after-free bugs.

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Most standard library headers are already included automatically for your convenience.

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OpenJDK 17 . Java 8 features such as lambda expressions and stream API can be used.

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Most standard library headers are already included automatically for your convenience.

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Includes Pair class from https://docs.oracle.com/javase/8/javafx/api/javafx/util/Pair.html.

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Python 2.7.12.

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C# 10 with .NET 6 runtime

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Ruby 3.1

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Some common data structure implementations are provided in the Algorithms module: https://www.rubydoc.info/github/kanwei/algorithms/Algorithms

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Swift 5.5.2.

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Go 1.17.6.

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Python 3.10.

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