1 files changed, 36 insertions, 0 deletions
diff --git a/string/suffixArray.cpp b/string/suffixArray.cpp
new file mode 100644
index 0000000..73c7aff
--- /dev/null
+++ b/string/suffixArray.cpp
@@ -0,0 +1,36 @@
+//longest common substring in one string (overlapping not excluded)
+//contains suffix array:--------------------------------------------------------------------
+int cmp(string &s,vector<vector<int>> &v, int i, int vi, int u, int l) {
+	int vi2 = (vi + 1) % 2, u2 = u + i / 2, l2 = l + i / 2; 
+	if(i == 1) return s[u] - s[l];
+	else if (v[vi2][u] != v[vi2][l]) return (v[vi2][u] - v[vi2][l]);
+	else { //beide groesser tifft nicht mehr ein, da ansonsten vorher schon unterschied in Laenge
+		if(u2 >= s.length()) return -1;
+		else if(l2 >= s.length()) return 1;
+		else return v[vi2][u2] - v[vi2][l2];
+	}
+}
+
+string lcsub(string s) {
+	if(s.length() == 0) return "";
+	vector<int> a(s.length());
+	vector<vector<int>> v(2, vector<int>(s.length(), 0));
+	int vi = 0;
+	for(int k = 0; k < a.size(); k++) a[k] = k;	
+	for(int i = 1; i <= s.length(); i *= 2, vi = (vi + 1) % 2) {
+		sort(a.begin(), a.end(), [&] (const int &u, const int &l) {
+			return cmp(s, v, i, vi, u, l) < 0;
+		});
+		v[vi][a[0]] = 0;
+		for(int z = 1; z < a.size(); z++) v[vi][a[z]] = v[vi][a[z-1]] + (cmp(s, v, i, vi, a[z], a[z-1]) == 0 ? 0 : 1);
+	}
+//-------------------------------------------------------------------------------------------
+	int r = 0, m=0, c=0;
+	for(int i = 0; i < a.size() - 1; i++) {
+		c = 0;
+		while(a[i]+c < s.length() && a[i+1]+c < s.length() && s[a[i]+c] == s[a[i+1]+c]) c++;
+		if(c > m) r=i, m=c;
+	}
+	return m == 0 ? "" : s.substr(a[r], m);
+}
+