151.Reverse_Words_in_a_String

Author: illuz

solutions/151.Reverse_Words_in_a_String/AC_reverse_n.c

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+/*
+*  Author:      illuz <iilluzen[at]gmail.com>
+*  Blog:        http://blog.csdn.net/hcbbt
+*  File:        AC_reverse_n.c
+*  Create Date: 2015-03-18 22:53:16
+*  Descripton:  O(1) space.
+*/
+
+#include <stdio.h>
+#include <string.h>
+
+void reverse_sub(char *s, int len) {
+    char tmp;
+    int i;
+    for (i = 0; i < len / 2; ++i) {
+        tmp = s[i];
+        s[i] = s[len - i - 1];
+        s[len - i - 1] = tmp;
+    }
+}
+
+void reverseWords(char *s) {
+    int i = 0;
+    int cur = 0;    // current pos of dealed string
+    int cnt = 0;    // current words' length
+    int word_cnt = 0;
+
+    while (1) {
+        // skip spaces
+        while (s[i] == ' ')
+            ++i;
+
+        if (s[i] == '\0')
+            break;
+
+        if (word_cnt++)
+            s[cur++] = ' ';
+        // count the length and move
+        cnt = 0;
+        while (s[i + cnt] != '\0' && s[i + cnt] != ' ') {
+            if (cur != i)
+                s[cur + cnt] = s[i + cnt];
+            cnt++;
+        }
+
+        reverse_sub(s + cur, cnt);
+
+        // update the pos and add space
+        i += cnt;
+        cur += cnt;
+    }
+    s[cur] = '\0';
+    reverse_sub(s, cur);
+}
+
+int main() {
+    char str[100];
+    while (gets(str)) {
+        printf("'%s'\n", str);
+        reverseWords(str);
+        printf("'%s'\n\n", str);
+    }
+    return 0;
+}
+

solutions/151.Reverse_Words_in_a_String/AC_split_n.java

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+/*
+*  Author:      illuz <iilluzen[at]gmail.com>
+*  File:        AC_split_n.java
+*  Create Date: 2015-03-18 22:30:59
+*  Descripton:   
+*/
+
+import java.util.*;
+
+public class Solution {
+    public String reverseWords(String s) {
+        String[] words = s.trim().split(" +");
+        int len = words.length;
+        if (len == 0) {
+            return "";
+        }
+        StringBuilder sb = new StringBuilder(words[len - 1]);
+        for (int i = len - 2; i >= 0; --i) {
+            sb.append(" " + words[i]);
+        }
+        return sb.toString();
+    }
+
+    // debug
+    public static void main(String[] args) {
+        Scanner cin = new Scanner(System.in);
+        Solution s = new Solution();
+        int[] input = {1, 2, 3, 4};
+        System.out.println("no case");
+    }
+}

solutions/151.Reverse_Words_in_a_String/AC_split_n.py

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+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+# Author:      illuz <iilluzen[at]gmail.com>
+# File:        AC_split_n.py
+# Create Date: 2015-03-18 21:49:19
+# Usage:       AC_split_n.py 
+# Descripton:  
+
+
+class Solution:
+    # @param s, a string
+    # @return a string
+    def reverseWords(self, s):
+        return ' '.join(list(reversed(s.split())))

solutions/151.Reverse_Words_in_a_String/AC_stringstream_n.cpp

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+/*
+*  Author:      illuz <iilluzen[at]gmail.com>
+*  File:        AC_stringstream_n.cpp
+*  Create Date: 2015-03-18 16:26:06
+*  Descripton:   
+*/
+
+#include <bits/stdc++.h>
+
+using namespace std;
+const int N = 0;
+
+class Solution {
+public:
+    void reverseWords(string &s) {
+        stringstream is(s);
+        is >> s;
+        string tmp;
+        while (is >> tmp)
+            s = tmp + ' ' + s;
+        if (s[0] == ' ')    // if input is all space then s will be the same
+            s = "";
+    }
+};
+
+int main() {
+    Solution s;
+    string str = "    ";
+    s.reverseWords(str);
+    cout << str << endl;
+    return 0;
+}
+