49 lines
1.0 KiB
C++
49 lines
1.0 KiB
C++
#include "s0151_reverse_words_in_a_string.hpp"
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void S0151::reverseSubStr(string &s, int begin, int end) {
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for (; begin < end; ++begin, --end) {
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char tmp = s[begin];
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s[begin] = s[end];
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s[end] = tmp;
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}
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}
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string S0151::reverseWords(string s) {
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if (s.length() == 0) {
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return s;
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}
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// remove extra spaces
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int len = s.length();
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int slow{0};
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for (int fast{0}; fast < len; ++fast) {
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if (s[fast] != ' ') {
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s[slow++] = s[fast];
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} else {
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if (fast == len - 1) {
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break;
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} else {
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if (s[fast + 1] != ' ' && slow != 0) {
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s[slow++] = ' ';
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}
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}
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}
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}
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s.resize(slow);
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// reverse the whole string
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len = s.length();
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reverseSubStr(s, 0, len - 1);
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// reverse each words
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for (int begin{0}, end{0}; end < len; ++end) {
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if (end == len - 1) {
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reverseSubStr(s, begin, end);
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} else {
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if (s[end + 1] == ' ') {
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reverseSubStr(s, begin, end);
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begin = end + 2;
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end = end + 1;
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}
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}
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}
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return s;
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}
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