[LeetCode]Text Justification

最新推荐文章于 2020-06-10 05:27:24 发布

原创最新推荐文章于 2020-06-10 05:27:24 发布 · 2.5k 阅读

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本文介绍了一种使用C++解决单词间距问题的方法，包括如何简化问题、处理字符串连接和添加空格，最终实现全行对齐和左对齐的文本格式化。

class Solution {
//simplify the problem
public:
	vector<string> fullJustify(vector<string> &words, int L) {
		// Start typing your C/C++ solution below
		// DO NOT write int main() function
		vector<string> ret;
		int begin = 0, len = 0, n = words.size();
		for (int i = 0; i < n; ++i) {
			if (len + words[i].size() + (i - begin) > L) {
				ret.push_back(connect(words, begin, i - 1, len, L, false));//push back one line
				begin = i;
				len = 0;
			} 
			len += words[i].size();
		}
		ret.push_back(connect(words, begin, n - 1, len, L, true));
		return ret;
	}

	string connect(vector<string> &words, int begin, int end, int len, int L, bool leftJustify) {
		string s;
		int n = end - begin + 1;
		for (int i = 0; i < n; ++i) {
			s += words[begin + i];
			addSpaces(s, i, n - 1, L - len, leftJustify);
		}

		if (s.size() < L) s.append(L - s.size(), ' ');
		return s;
	}

	void addSpaces(string &s, int i, int n, int L, bool leftJustify) {
		if (n < 1 || i > n - 1) return;
		int spaces = leftJustify ? 1 : (L / n + (i < (L % n) ? 1 : 0));
		s.append(spaces, ' ');
	}
};

second time

class Solution {
public:
    string leftJustified(int L, vector<string>& words, int start, int end)
    {
        string ans;
        for(int i = start; i < end; ++i)
        {
            ans = ans+words[i];
            ans.push_back(' ');
        }
        ans = ans+words[end];
        int curCnt = 0;
        for(int i = start; i <= end; ++i) curCnt += words[i].size();
        curCnt += (end-start);
        int lastCnt = L-curCnt;
        ans.append(lastCnt, ' ');
        return ans;
    }
    string evenJustified(int L, vector<string>& words, int start, int end)
    {
        int curCnt = 0;
        for(int i = start; i <= end; ++i) curCnt += words[i].size();
        curCnt += (end-start);
        int leftCnt = L-curCnt;
        string ans;
        if(end-start >= 1)
        {
            int addCnt = leftCnt/(end-start);
            int extraCnt = leftCnt%(end-start);
            
            for(int i = start, j = 1; i < end; ++i, ++j)
            {
                int spaceCnt = 1+addCnt;
                if(j <= extraCnt) spaceCnt++;
                ans = ans+words[i];
                ans.append(spaceCnt, ' ');
            }
            ans = ans+words[end];
        }
        else
        {
            ans = ans+words[end];
            ans.append(L-words[end].size(), ' ');
        }       
        return ans;
    }
    vector<string> fullJustify(vector<string> &words, int L) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if(words.size() == 0 || L == 0) return words; 
        int start = 0;
        vector<string> ans;
        while(start < words.size())
        {
            int curWordLen = 0;
            int curWordCnt = 0;
            int i;
            for(i = start; i < words.size(); ++i)
            {
                curWordLen += words[i].size();
                curWordCnt++;
                if(curWordLen+curWordCnt-1 > L)
                {
                    i--;
                    break;
                }
            }
            if(i == words.size())
            {
                i--;
                string tmp = leftJustified(L, words, start, i);
                ans.push_back(tmp);
            }
            else
            {
                string tmp = evenJustified(L, words, start, i);
                ans.push_back(tmp);
            }
           
            start = i+1;
        }
        return ans;
    }
};