Data commit

Task/Longest-common-subsequence/JavaScript/longest-common-subsequence-1.js

@@ -0,0 +1,14 @@
+function lcs(a, b) {
+  var aSub = a.substr(0, a.length - 1);
+  var bSub = b.substr(0, b.length - 1);
+
+  if (a.length === 0 || b.length === 0) {
+    return '';
+  } else if (a.charAt(a.length - 1) === b.charAt(b.length - 1)) {
+    return lcs(aSub, bSub) + a.charAt(a.length - 1);
+  } else {
+    var x = lcs(a, bSub);
+    var y = lcs(aSub, b);
+    return (x.length > y.length) ? x : y;
+  }
+}

Task/Longest-common-subsequence/JavaScript/longest-common-subsequence-2.js

@@ -0,0 +1,10 @@
+const longest = (xs, ys) => (xs.length > ys.length) ? xs : ys;
+
+const lcs = (xx, yy) => {
+  if (!xx.length || !yy.length) { return ''; }
+
+  const [x, ...xs] = xx;
+  const [y, ...ys] = yy;
+
+  return (x === y) ? (x + lcs(xs, ys)) : longest(lcs(xx, ys), lcs(xs, yy));
+};

Task/Longest-common-subsequence/JavaScript/longest-common-subsequence-3.js

@@ -0,0 +1,35 @@
+function lcs(x,y){
+	var s,i,j,m,n,
+		lcs=[],row=[],c=[],
+		left,diag,latch;
+	//make sure shorter string is the column string
+	if(m<n){s=x;x=y;y=s;}
+	m = x.length;
+	n = y.length;
+	//build the c-table
+	for(j=0;j<n;row[j++]=0);
+	for(i=0;i<m;i++){
+		c[i] = row = row.slice();
+		for(diag=0,j=0;j<n;j++,diag=latch){
+			latch=row[j];
+			if(x[i] == y[j]){row[j] = diag+1;}
+			else{
+				left = row[j-1]||0;
+				if(left>row[j]){row[j] = left;}
+			}
+		}
+	}
+	i--,j--;
+	//row[j] now contains the length of the lcs
+	//recover the lcs from the table
+	while(i>-1&&j>-1){
+		switch(c[i][j]){
+			default: j--;
+				lcs.unshift(x[i]);
+			case (i&&c[i-1][j]): i--;
+				continue;
+			case (j&&c[i][j-1]): j--;
+		}
+	}
+	return lcs.join('');
+}

Task/Longest-common-subsequence/JavaScript/longest-common-subsequence-4.js

@@ -0,0 +1,15 @@
+	var t=i;
+	while(i>-1&&j>-1){
+		switch(c[i][j]){
+			default:i--,j--;
+				continue;
+			case (i&&c[i-1][j]):
+				if(t!==i){lcs.unshift(x.substring(i+1,t+1));}
+				t=--i;
+				continue;
+			case (j&&c[i][j-1]): j--;
+				if(t!==i){lcs.unshift(x.substring(i+1,t+1));}
+				t=i;
+		}
+	}
+	if(t!==i){lcs.unshift(x.substring(i+1,t+1));}

Task/Longest-common-subsequence/JavaScript/longest-common-subsequence-5.js

@@ -0,0 +1,42 @@
+function lcs_greedy(x,y){
+  var p1, i, idx,
+      symbols = {},
+      r = 0,
+      p = 0,
+      l = 0,
+      m = x.length,
+      n = y.length,
+      s = new Buffer((m < n) ? n : m);
+
+  p1 = popsym(0);
+
+  for (i = 0; i < m; i++) {
+    p = (r === p) ? p1 : popsym(i);
+    p1 = popsym(i + 1);
+    if (p > p1) {
+      i += 1;
+      idx = p1;
+    } else {
+      idx = p;
+    }
+
+    if (idx === n) {
+      p = popsym(i);
+    } else {
+      r = idx;
+      s[l] = x.charCodeAt(i);
+      l += 1;
+    }
+  }
+  return s.toString('utf8', 0, l);
+	
+  function popsym(index) {
+    var s = x[index],
+        pos = symbols[s] + 1;
+
+    pos = y.indexOf(s, ((pos > r) ? pos : r));
+    if (pos === -1) { pos = n; }
+    symbols[s] = pos;
+    return pos;
+  }
+}

Task/Longest-common-subsequence/JavaScript/longest-common-subsequence-6.js

@@ -0,0 +1 @@
+lcs_greedy('bcaaaade', 'deaaaabc'); // 'bc' instead of 'aaaa'