8

Author: retaw

.gitignore

@@ -1,3 +1,4 @@
 *.exec
 *.swp
 a.out
+t.cpp

3_longest_substring_without_repeating_characters.cpp

@@ -2,6 +2,7 @@
 
 class Solution {
 public:
+    /*
     int lengthOfLongestSubstring(string s)
     {
         int ret = 0;
@@ -26,6 +27,31 @@ class Solution {
             ret = i - subStrBegin;
         return ret;
     }
+*/
+    int lengthOfLongestSubstring(string s)
+    {
+        int ret = 0;
+        int subStrBegin = 0;
+        int lastPosOfChar[256]; //用已出现过的字符索引的表, 下标为字符，值为出现位置
+        for(int i = 0; i < 256; ++i)
+            lastPosOfChar[i] = -1;
+
+        const int size = s.size();
+        for(int i = 0; i < size; ++i)
+        {
+            int ch = s[i];
+            if(lastPosOfChar[ch] >= subStrBegin) //已经出现过且在子本字符串内
+            {
+                if(ret < i - subStrBegin)
+                    ret = i - subStrBegin ;
+                subStrBegin = lastPosOfChar[ch] + 1;
+            }
+            lastPosOfChar[ch] = i;
+        }
+        if(ret < size - subStrBegin)
+            ret = size - subStrBegin;
+        return ret;
+    }
 };
 
 

8_string_to_interger.cpp

@@ -0,0 +1,50 @@
+#include "test.h"
+
+class Solution {
+public:
+    int myAtoi(string str)
+    {
+        int64_t ret = 0;
+
+        int sign = 1;
+
+        bool discarding = true;
+
+        for(char ch : str)
+        {
+            if(discarding && (ch == ' ' || ch == '0'))
+                continue;
+
+            if(discarding && ch == '-')
+            {
+                sign = -1;
+            }
+            else if(discarding && ch == '+')
+            {
+            }
+            else if(ch >= '0' && ch <= '9')
+            {
+                ret *= 10;
+                ret +=  (ch - '0');
+            }
+            else
+            {
+                break;
+            }
+
+            discarding = false;
+
+            if(ret > 0x7fffffff)
+                return sign == 1 ? 0x7fffffff : 0x80000000;
+        }
+
+        return sign * ret;
+    }
+};
+
+
+int main()
+{
+    Solution s;
+    cout << s.myAtoi("   -123b") << endl;
+}

Makefile

@@ -6,6 +6,7 @@ targets = \
 	5_longest_palindromic_substring.exec\
 	6_zigzag_conversion.exec\
 	7_reverse_interger.exec\
+	8_string_to_interger.exec\
 
 
 CC = g++