Dynamic Programming

//The two sequences to compare

    var sequence1 = "GAATTCAGTTA"

    var sequence2 = "GGATCGA"

​

//Creates multi-dimensional array dependent on sequence lengths

  var arr = new Array(sequence2.length+1)

    for(i=0;i<sequence2.length+1;i++){

      arr[i] = new Array(sequence1.length+1);

    }

​

//Fills array with 0s

  for(i=0;i<arr.length;i++){

    var col = i;

    for(j=0;j<arr[col].length;j++){

      arr[col][j]=0;

    }

  }

​

//Matrix Fill

for(i=1;i<arr.length;i++){

  var col = i;

  for(j=1;j<sequence1.length+1;j++){

    if(arr[col][j-1]>arr[col][j]){

      arr[col][j]=arr[col][j-1]

    }

    if(arr[col-1][j]>arr[col][j]){

      arr[col][j]=arr[col-1][j];

    }

    var match = 0;

    if(sequence2[col-1]==sequence1[j-1]){

      match = 1;

    }

    if((arr[col-1][j-1]+match)>arr[col][j]){

      arr[col][j]=(arr[col-1][j-1])+match;

    }

  } 

}

​

console.table(arr);

​