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| 1 | +// https://leetcode.com/problems/is-subsequence/description/ |
| 2 | +import 'package:test/test.dart'; |
| 3 | + |
| 4 | +void main() { |
| 5 | + final stopwatch = Stopwatch()..start(); |
| 6 | + runTests(); |
| 7 | + |
| 8 | + /// |
| 9 | + stopwatch.stop(); |
| 10 | + print('Function Execution Time : ${stopwatch.elapsedMicroseconds} micro sec'); |
| 11 | +} |
| 12 | + |
| 13 | +class Solution { |
| 14 | + |
| 15 | + ////! Done from first time TC: O(n) |
| 16 | + bool isSubsequence(String s, String t) { |
| 17 | + if (s.isEmpty) return true; |
| 18 | + if (s.isEmpty) return false; |
| 19 | + |
| 20 | + int sIndex = 0; |
| 21 | + for (var i = 0; i < t.length; i++) { |
| 22 | + if (s[sIndex] == t[i]) { |
| 23 | + sIndex++; |
| 24 | + if (sIndex >= s.length) return true; |
| 25 | + } |
| 26 | + } |
| 27 | + |
| 28 | + return false; |
| 29 | + } |
| 30 | +} |
| 31 | + |
| 32 | +void runTests() { |
| 33 | + final Solution s = Solution(); |
| 34 | + |
| 35 | + group('Is Subsequence', () { |
| 36 | + // Basic examples from problem statement |
| 37 | + test('Example 1: s="abc", t="ahbgdc" → true', () { |
| 38 | + expect(s.isSubsequence("abc", "ahbgdc"), isTrue); |
| 39 | + }); |
| 40 | + |
| 41 | + test('Example 2: s="axc", t="ahbgdc" → false', () { |
| 42 | + expect(s.isSubsequence("axc", "ahbgdc"), isFalse); |
| 43 | + }); |
| 44 | + |
| 45 | + // Edge cases |
| 46 | + test('Empty s: s="", t="ahbgdc" → true', () { |
| 47 | + expect(s.isSubsequence("", "ahbgdc"), isTrue); |
| 48 | + }); |
| 49 | + |
| 50 | + test('Empty t: s="abc", t="" → false', () { |
| 51 | + expect(s.isSubsequence("abc", ""), isFalse); |
| 52 | + }); |
| 53 | + |
| 54 | + test('Both empty: s="", t="" → true', () { |
| 55 | + expect(s.isSubsequence("", ""), isTrue); |
| 56 | + }); |
| 57 | + |
| 58 | + // Single character cases |
| 59 | + test('Single char match: s="a", t="abc" → true', () { |
| 60 | + expect(s.isSubsequence("a", "abc"), isTrue); |
| 61 | + }); |
| 62 | + |
| 63 | + test('Single char no match: s="d", t="abc" → false', () { |
| 64 | + expect(s.isSubsequence("d", "abc"), isFalse); |
| 65 | + }); |
| 66 | + |
| 67 | + // Exact match |
| 68 | + test('Exact match: s="abc", t="abc" → true', () { |
| 69 | + expect(s.isSubsequence("abc", "abc"), isTrue); |
| 70 | + }); |
| 71 | + |
| 72 | + // Non-consecutive matches |
| 73 | + test('Non-consecutive match: s="ace", t="abcde" → true', () { |
| 74 | + expect(s.isSubsequence("ace", "abcde"), isTrue); |
| 75 | + }); |
| 76 | + |
| 77 | + test('Non-consecutive no match: s="aec", t="abcde" → false', () { |
| 78 | + expect(s.isSubsequence("aec", "abcde"), isFalse); |
| 79 | + }); |
| 80 | + |
| 81 | + // Repeated characters |
| 82 | + test('Repeated chars match: s="aabb", t="aaabbb" → true', () { |
| 83 | + expect(s.isSubsequence("aabb", "aaabbb"), isTrue); |
| 84 | + }); |
| 85 | + |
| 86 | + test('Repeated chars no match: s="aabb", t="ababab" → false', () { |
| 87 | + expect(s.isSubsequence("aabb", "ababab"), isTrue); |
| 88 | + }); |
| 89 | + |
| 90 | + // Large strings |
| 91 | + test('Large t string with match', () { |
| 92 | + final t = '${List.generate(10000, (i) => 'a').join()}b'; |
| 93 | + expect(s.isSubsequence("ab", t), isTrue); |
| 94 | + }); |
| 95 | + |
| 96 | + test('Large t string without match', () { |
| 97 | + final t = List.generate(10000, (i) => 'a').join(); |
| 98 | + expect(s.isSubsequence("b", t), isFalse); |
| 99 | + }); |
| 100 | + |
| 101 | + // s longer than t |
| 102 | + test('s longer than t: s="abcd", t="abc" → false', () { |
| 103 | + expect(s.isSubsequence("abcd", "abc"), isFalse); |
| 104 | + }); |
| 105 | + |
| 106 | + // Maximum constraints |
| 107 | + test('Maximum length t with early match', () { |
| 108 | + final t = 'z${List.generate(9999, (i) => 'a').join()}'; |
| 109 | + expect(s.isSubsequence("za", t), isTrue); |
| 110 | + }); |
| 111 | + |
| 112 | + // Special cases |
| 113 | + test('All same characters: s="aaa", t="aaab" → true', () { |
| 114 | + expect(s.isSubsequence("aaa", "aaab"), isTrue); |
| 115 | + }); |
| 116 | + |
| 117 | + test('All same characters no match: s="aaaa", t="aaa" → false', () { |
| 118 | + expect(s.isSubsequence("aaaa", "aaa"), isFalse); |
| 119 | + }); |
| 120 | + |
| 121 | + // Random cases |
| 122 | + test('Random case 1: s="hello", t="hheelllloo" → true', () { |
| 123 | + expect(s.isSubsequence("hello", "hheelllloo"), isTrue); |
| 124 | + }); |
| 125 | + |
| 126 | + test('Random case 2: s="world", t="wrrroldd" → false', () { |
| 127 | + expect(s.isSubsequence("world", "wrrroldd"), isFalse); |
| 128 | + }); |
| 129 | + }); |
| 130 | +} |
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