leetcode 102: Substring with Concatenation of All Words
Substring with Concatenation of All WordsFeb
24 '12
You are given a string, S, and a list of words, L, that are all of the same length. Find all starting indices of substring(s) in S that is a concatenation of each word in L exactly once and without any intervening characters.
For example, given:
S: "barfoothefoobarman"
L: ["foo",
"bar"]
You should return the indices: [0,9]
.
(order does not matter).
public class Solution { public ArrayList<Integer> findSubstring(String S, String[] L) { // Start typing your Java solution below // DO NOT write main() function ArrayList<Integer> res = new ArrayList<Integer>(); if(S==null || L==null || L.length==0) return res; HashMap<String, Integer> map = new HashMap<String, Integer>(); for(int i=0; i<L.length; i++){ if(map.containsKey( L[i] ) ){ map.put(L[i], map.get(L[i])+1); } else { map.put(L[i], 1); } } int sz= S.length(); int m=L[0].length(); int n=L.length; for(int i=0; i<sz-n*m+1;i++) { HashMap<String, Integer> temp = new HashMap<String, Integer>(map); for(int j=i; j<i+n*m;j+=m) { String t = S.substring(j,j+m); if( temp.containsKey(t) ){ int x=temp.get(t); if(x==1) temp.remove(t); else temp.put(t, x-1); } else { break; } if(temp.isEmpty()) { res.add(i); } } } return res; } }