Suffix Array - Codeforces Education

Author: azecoder

Education/SuffixArray.cpp

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+#include <bits/stdc++.h>
+
+#define MX 1e4+5
+
+using namespace std;
+
+typedef pair<int, int> pii;
+typedef vector<int> vi;
+typedef vector<pii> vii;
+typedef pair<char, int> pci;
+typedef vector<pci> vci;
+
+
+int main() {
+
+	string s;
+	cin >> s;
+	
+	s += "$";
+	int n = s.size();
+	
+	vi sufInd(n), sufClass(n);
+	{
+		vci sufArr(n);
+		for(int i = 0; i < n; i++)
+			sufArr[i] = {s[i], i};
+		sort(sufArr.begin(), sufArr.end());
+		
+		for(int i = 0; i < n; i++)
+			sufInd[i] = sufArr[i].second;
+			
+		sufClass[sufInd[0]] = 0;
+		for(int i = 1; i < n; i++)
+			if (sufArr[i].first == sufArr[i-1].first)
+				sufClass[sufInd[i]] = sufClass[sufInd[i-1]];
+			else
+				sufClass[sufInd[i]] = sufClass[sufInd[i-1]] + 1;
+	}
+	
+	int k = 0;
+	while((1 << k) < n) {
+		vector<pair<pii, int>> sufArr(n);
+		for(int i = 0; i < n; i++)
+			sufArr[i] = {{sufClass[i], sufClass[(i + (1 << k)) % n]}, i};
+		sort(sufArr.begin(), sufArr.end());
+		
+		for(int i = 0; i < n; i++)
+			sufInd[i] = sufArr[i].second;
+		
+		sufClass[sufInd[0]] = 0;
+		for(int i = 1; i < n; i++)
+			if (sufArr[i].first == sufArr[i-1].first)
+				sufClass[sufInd[i]] = sufClass[sufInd[i-1]];
+			else
+				sufClass[sufInd[i]] = sufClass[sufInd[i-1]] + 1;
+	
+		k++;
+	}
+	
+	for(int x: sufInd)
+		cout << x << " ";
+	cout << "\n";
+
+	return 0;
+}