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Longest common subsequence #186

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Merged
TornjV merged 2 commits into from
Jun 17, 2016
Merged

Longest common subsequence #186

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8ab9b80
Longest Common Subsequence
archie94 Jun 17, 2016
1a94b57
Modify category.json
archie94 Jun 17, 2016
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1 change: 1 addition & 0 deletions algorithm/category.json
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@
"integer_partition": "Integer Partition",
"knapsack_problem": "Knapsack Problem",
"longest_increasing_subsequence": "Longest Increasing Subsequence",
"longest_common_subsequence": "Longest Common Subsequence",
"max_subarray": "Maximum Subarray",
"max_sum_path": "Maximum Sum Path",
"pascal_triangle": "Pascal's Triangle",
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36 changes: 36 additions & 0 deletions algorithm/dp/longest_common_subsequence/basic/code.js
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Original file line number Diff line number Diff line change
@@ -0,0 +1,36 @@
var i,j;

// Build the memo table in bottom up fashion
for( i = 0; i <= m; i++ ) {
for( j = 0; j <= n; j++ ) {
if ( i === 0 || j === 0 ) {
A[i][j] = 0;
} 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] = A[i-1][j];
} else {
A[i][j] = 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 ( 'Longest Common Subsequence is ' + A[m][n] );
13 changes: 13 additions & 0 deletions algorithm/dp/longest_common_subsequence/basic/data.js
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@@ -0,0 +1,13 @@
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/longest_common_subsequence/desc.json
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{
"Longest Common Subsequence": "The longest common subsequence (LCS) problem is the problem of finding the longest subsequence common to all sequences in a set of sequences (often just two sequences)." ,
"Complexity": {
"time": "O(mn)",
"space": "O(mn)"
},
"References": [
"<a href='https://en.wikipedia.org/wiki/Longest_common_subsequence_problem'>Wikipedia</a>"
],
"files": {
"basic": "Longest common subsequence"
}
}