LeetCode Text Justification

 1 #include <iostream>

 2 #include <cstdlib>

 3 #include <string>

 4 #include <vector>

 5 

 6 using namespace std;

 7 

 8 class Solution {

 9 public:

10     vector<string> fullJustify(vector<string> &words, int L) {

11         int len = words.size();

12         vector<string> res;

13         if (L < 1) {

14             res.push_back(string(""));

15             return res;

16         }

17         int pos = 0;

18 

19         while (pos < len) {

20             int pre_pos = pos;

21             int llen = words[pos++].size();

22 

23             while (pos < len) {

24                 if (llen + 1 + words[pos].length() > L) {

25                     break;

26                 }

27                 llen = llen + 1 + words[pos++].length();

28             }

29             bool last_line = pos >= len;

30             

31             int wcnt = pos - pre_pos;       // number of words in one line

32             int wlen = llen - (wcnt - 1);   // length of words in one line

33             int space= L - wlen;            // space in one line

34 

35             string line;

36             bool left_justify = last_line || wcnt == 1;

37 

38             // avg space if space can be distributed evenly, it should be a integer

39             // or it will be a float and rounded to a integer

40             int avg_space = 0;

41             

42             // when the avg space has been rounded, ext_space indicates the lost spaces

43             int ext_space = 0;

44             

45             // be sure that zero divide will not happend

46             // last line do not need avg_space and ext_space

47             if (!left_justify) {

48                 avg_space = space / (wcnt - 1);

49                 ext_space = space - avg_space * (wcnt - 1);

50             }

51             // start to build a line

52             line = words[pre_pos];

53 

54             for (int i=1; i<wcnt; i++) {

55                 if (left_justify) {

56                     line.push_back(' ');

57                 } else {

58                     line.append(string((ext_space-- > 0 ? 1 : 0) + avg_space, ' '));

59                 }

60                 line.append(words[pre_pos + i]);

61             }

62             if (line.size() < L) {

63                 line.append(string(L - line.size(), ' '));

64             }

65             res.push_back(line);

66         }

67         

68         return res;

69     }

70 };

71 

72 

73 void print(vector<string>& s) {

74     for (int i=0; i<s.size(); i++) {

75         cout<<s[i]<<"|"<<endl;

76     }

77 }

78 int main() {

79     Solution s;

80     const char* w[] = {"Listen","to","many,","speak","to","a","few."};

81     vector<string> words(w, w + sizeof(w) / sizeof(const char*));

82     words.push_back(string(""));

83 

84     vector<string> res = s.fullJustify(words, 6);

85 

86     print(res);

87     system("pause");

88     return 0;

89 }

关键是明确需求