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SCS is a string Z which is the shortest supersequence of strings X and Y (may not be continuous in Z, but order is maintained). More...
#include <iostream>#include <string>#include <vector>#include <algorithm>#include <cassert>
Go to the source code of this file.
SCS is a string Z which is the shortest supersequence of strings X and Y (may not be continuous in Z, but order is maintained).
The idea is to use lookup table method as used in LCS. For example: example 1:- X: 'ABCXYZ', Y: 'ABZ' then Z will be 'ABCXYZ' (y is not continuous but in order)
For example: example 2:- X: 'AGGTAB', Y: 'GXTXAYB' then Z will be 'AGGXTXAYB'
Definition in file shortest_common_supersequence.cpp.
◆ main()Main function (driver code)
Definition at line 164 of file shortest_common_supersequence.cpp.
164 {
165
167
168
169 std::string s1, s2;
170 std::cin >> s1;
171 std::cin >> s2;
172
173 std::string ans;
174
175
177 std::cout << ans;
178 return 0;
179}
std::string scs(const std::string &str1, const std::string &str2)
◆ scs() std::string dynamic_programming::shortest_common_supersequence::scs ( const std::string & str1, const std::string & str2 )Function implementing Shortest Common Super-Sequence algorithm using look-up table method.
Definition at line 42 of file shortest_common_supersequence.cpp.
42 {
43
44
45
46 if(str1.empty() && str2.empty()) {
47 return "";
48 }
49 else if(str1.empty()) {
50 return str2;
51 }
52 else if(str2.empty()) {
53 return str1;
54 }
55
56
57 std::vector <std::vector <int>> lookup(str1.length() + 1, std::vector <int> (str2.length() + 1, 0));
58
59 for(int i=1; i <= str1.length(); i++) {
60 for(int j=1; j <= str2.length(); j++) {
61 if(str1[i-1] == str2[j-1]) {
62 lookup[i][j] = lookup[i-1][j-1] + 1;
63 }
64 else {
65 lookup[i][j] = std::max(lookup[i-1][j], lookup[i][j-1]);
66 }
67 }
68 }
69
70
71
72
73 int i=str1.length();
74 int j=str2.length();
75 std::string s;
76
77 while(i>0 && j>0) {
78
79
80
81 if(str1[i-1] == str2[j-1]) {
82 s.push_back(str1[i-1]);
83 i--;
84 j--;
85 }
86
87 else {
88 if(lookup[i-1][j] > lookup[i][j-1]) {
89 s.push_back(str1[i-1]);
90 i--;
91 }
92 else {
93 s.push_back(str2[j-1]);
94 j--;
95 }
96 }
97 }
98
99
100
101 while(i > 0) {
102 s.push_back(str1[i-1]);
103 i--;
104 }
105
106
107 while(j > 0) {
108 s.push_back(str2[j-1]);
109 j--;
110 }
111
112
113
114 reverse(s.begin(), s.end());
115 return s;
116 }
◆ test()Test Function
Definition at line 124 of file shortest_common_supersequence.cpp.
124 {
125
126 std::vector <std::vector <std::string>> scsStrings {
127 {"ABCXYZ", "ABZ"},
128 {"ABZ", "ABCXYZ"},
129 {"AGGTAB", "GXTXAYB"},
130 {"X", "Y"},
131 };
132
133
134 std::vector <std::string> calculatedOutput(4, "");
135 int i=0;
136 for(auto & scsString : scsStrings) {
137
139 scsString[0], scsString[1]
140 );
141 i++;
142 }
143
144
145 std::vector <std::string> expectedOutput {
146 "ABCXYZ",
147 "ABCXYZ",
148 "AGGXTXAYB",
149 "XY"
150 };
151
152
153
154
155 for(int i=0; i < scsStrings.size(); i++) {
156 assert(expectedOutput[i] == calculatedOutput[i]);
157 }
158
159 std::cout << "All tests passed successfully!\n";
160 return;
161}
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