find_word.py

def find_word_concatenation(s, words):
    result_indices = []
    worddict = dict()
    wordlen = len(words[0])
    i, j = 0, 0
    total = 0
    for word in words:
        if word not in worddict:
            worddict[word] = 0
        worddict[word] += 1
        total += len(word)
    cnt = len(worddict)
    while j < len(s):
        cur = s[j:j+wordlen]
        if cur not in worddict:
            j += 1
            continue
        if cur in worddict:
            worddict[cur] -= 1
            if worddict[cur] == 0:
                cnt -= 1
       
        while cnt == 0 and i < j:
            if j + wordlen - i == total:
                result_indices.append(i)
            w = s[i: i+wordlen]
            if w not in worddict:
                i += 1
                continue
            worddict[w] += 1
            if worddict[w] > 0:
                cnt += 1
            i += wordlen
        j += wordlen
    return result_indices