TopCoder srm630,div1,500, suffix array __topcoder

Meaning

Gives a string of the array of suffixes after the sort of SA array, allowing you to construct a string so that the prefix array sa array and the given SA array, ask you at least how many different characters to construct the string.

Analysis:

Understanding suffix array: sa[], rank[], height[] meaning.

Suppose there are two suffixes A and B, and if a<b, there are two things that can be satisfied:

①A[0]<B[0]

②a[0]=b[0], and a suffix array starting with a[1 < A suffix array starting with b[1]

In order to ensure that the type of characters used is the least, the first choice of the first ② of the situation to consider, if the ② is not satisfied, according to ① to construct.

Specific implementation code:

#include <vector>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
# Include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>

using namespace std;

Class SuffixArrayDiv1 {public
:
	int minimalcharacters (vector <int>);
	int rank[55];

int suffixarraydiv1::minimalcharacters (vector <int> SA) {
	int sz=sa.size ();
	for (int i=0;i<sz;i++)
	{
		rank[sa[i]]=i
	}
	Rank[sz]=-1;
	int Ans=1;
	for (int i=0;i<sz-1;i++)
	{
		if (rank[sa[i]+1]>rank[sa[i+1]+1]) ans++; 
	}
	return ans;
}

<%:testing-code%>
//powered by [Kawigiedit] 2.0!