A-M baby

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

@@ -0,0 +1,27 @@
+function lcs_greedy(x,y){
+	var symbols = {},
+		r=0,p=0,p1,L=0,idx,
+		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);
+		idx=(p > p1)?(i++,p1):p;
+		if(idx===n){p=popsym(i);}
+		else{
+			r=idx;
+			S[L++]=x.charCodeAt(i);
+		}
+	}
+	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;
+	}
+}