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Shortest Common Supersequence algorithm #191

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Merged
TornjV merged 2 commits into from
Jun 22, 2016
Merged

Shortest Common Supersequence algorithm #191

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c951391
Shortest common supersequence algorithm
archie94 Jun 22, 2016
9243c40
Arrange LCS alphabetically
archie94 Jun 22, 2016
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3 changes: 2 additions & 1 deletion algorithm/category.json
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Original file line number Diff line number Diff line change
Expand Up @@ -18,11 +18,12 @@
"fibonacci": "Fibonacci Sequence",
"integer_partition": "Integer Partition",
"knapsack_problem": "Knapsack Problem",
"longest_increasing_subsequence": "Longest Increasing Subsequence",
"longest_common_subsequence": "Longest Common Subsequence",
"longest_increasing_subsequence": "Longest Increasing Subsequence",
"max_subarray": "Maximum Subarray",
"max_sum_path": "Maximum Sum Path",
"pascal_triangle": "Pascal's Triangle",
"shortest_common_supersequence": "Shortest Common Supersequence",
"sliding_window": "Sliding Window",
"ugly_numbers": "Ugly Numbers"
},
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38 changes: 38 additions & 0 deletions algorithm/dp/shortest_common_supersequence/basic/code.js
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@@ -0,0 +1,38 @@
var i,j;

// Fill memo table in bottom up manner
for ( i = 0; i <= m; i++ ) {
for ( j = 0; j <= n; j++ ) {
if( i === 0 ) {
A[i][j] = j;
} else if ( j === 0 ) {
A[i][j] = i;
} else if ( string1[i-1] == string2[j-1] ) {
tracer1._select ( i-1 )._wait ();
tracer2._select ( j-1 )._wait ();
tracer3._select ( i-1, j-1 )._wait ();

A[i][j] = A[i-1][j-1] + 1;

tracer1._deselect ( i-1 );
tracer2._deselect ( j-1 );
tracer3._deselect ( i-1, j-1 );
} else {
tracer3._select ( i-1, j )._wait ();
tracer3._select ( i, j-1 )._wait ();

if ( A[i-1][j] < A[i][j-1] ) {
A[i][j] = 1 + A[i-1][j];
} else {
A[i][j] = 1 + A[i][j-1];
}

tracer3._deselect ( i-1, j );
tracer3._deselect ( i, j-1 );
}
tracer3._notify ( i, j , A[i][j] )._wait ();
tracer3._denotify( i, j );
}
}

logger._print ( 'Shortest Common Supersequence is ' + A[m][n] );
13 changes: 13 additions & 0 deletions algorithm/dp/shortest_common_supersequence/basic/data.js
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var string1 = 'AGGTAB';
var string2 = 'GXTXAYB';
var m = string1.length;
var n = string2.length;
var A = new Array (m+1);
for (var i = 0; i < m+1; i++ ) {
A[i] = new Array (n+1);
}

var tracer1 = new Array1DTracer ( 'String 1')._setData ( string1 );
var tracer2 = new Array1DTracer ( 'String 2')._setData ( string2 );
var tracer3 = new Array2DTracer ( 'Memo Table')._setData ( A );
var logger = new LogTracer ();
13 changes: 13 additions & 0 deletions algorithm/dp/shortest_common_supersequence/desc.json
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{
"Shortest Common Supersequence": "n computer science, the shortest common supersequence problem is a problem closely related to the longest common subsequence problem. Given two sequences X = < x1,...,xm > and Y = < y1,...,yn >, a sequence U = < u1,...,uk > is a common supersequence of X and Y if U is a supersequence of both X and Y. In other words, a shortest common supersequence of strings x and y is a shortest string z such that both x and y are subsequences of z." ,
"Complexity": {
"time": "O(mn)",
"space": "O(mn)"
},
"References": [
"<a href='https://en.wikipedia.org/wiki/Shortest_common_supersequence_problem'>Wikipedia</a>"
],
"files": {
"basic": "Shortest common supersequence"
}
}